text
stringlengths
81
112k
Encodes a list of strings to a single string. :type strs: List[str] :rtype: str def encode(strs): """Encodes a list of strings to a single string. :type strs: List[str] :rtype: str """ res = '' for string in strs.split(): res += str(len(string)) + ":" + string return res
Decodes a single string to a list of strings. :type s: str :rtype: List[str] def decode(s): """Decodes a single string to a list of strings. :type s: str :rtype: List[str] """ strs = [] i = 0 while i < len(s): index = s.find(":", i) size = int(s[i:index]) str...
:type A: List[List[int]] :type B: List[List[int]] :rtype: List[List[int]] def multiply(multiplicand: list, multiplier: list) -> list: """ :type A: List[List[int]] :type B: List[List[int]] :rtype: List[List[int]] """ multiplicand_row, multiplicand_col = len( multiplicand), len(mu...
This function calculates nCr. def combination(n, r): """This function calculates nCr.""" if n == r or r == 0: return 1 else: return combination(n-1, r-1) + combination(n-1, r)
This function calculates nCr using memoization method. def combination_memo(n, r): """This function calculates nCr using memoization method.""" memo = {} def recur(n, r): if n == r or r == 0: return 1 if (n, r) not in memo: memo[(n, r)] = recur(n - 1, r - 1) + recur(...
:type s: str :type t: str :rtype: bool def is_anagram(s, t): """ :type s: str :type t: str :rtype: bool """ maps = {} mapt = {} for i in s: maps[i] = maps.get(i, 0) + 1 for i in t: mapt[i] = mapt.get(i, 0) + 1 return maps == mapt
Pancake_sort Sorting a given array mutation of selection sort reference: https://www.geeksforgeeks.org/pancake-sorting/ Overall time complexity : O(N^2) def pancake_sort(arr): """ Pancake_sort Sorting a given array mutation of selection sort reference: https://www.geeksforgee...
:rtype: int def next(self): """ :rtype: int """ v=self.queue.pop(0) ret=v.pop(0) if v: self.queue.append(v) return ret
:type prices: List[int] :rtype: int def max_profit_naive(prices): """ :type prices: List[int] :rtype: int """ max_so_far = 0 for i in range(0, len(prices) - 1): for j in range(i + 1, len(prices)): max_so_far = max(max_so_far, prices[j] - prices[i]) return max_so_far
input: [7, 1, 5, 3, 6, 4] diff : [X, -6, 4, -2, 3, -2] :type prices: List[int] :rtype: int def max_profit_optimized(prices): """ input: [7, 1, 5, 3, 6, 4] diff : [X, -6, 4, -2, 3, -2] :type prices: List[int] :rtype: int """ cur_max, max_so_far = 0, 0 for i in range(1, len(pr...
:type s: str :rtype: int def first_unique_char(s): """ :type s: str :rtype: int """ if (len(s) == 1): return 0 ban = [] for i in range(len(s)): if all(s[i] != s[k] for k in range(i + 1, len(s))) == True and s[i] not in ban: return i else: ...
:type root: TreeNode :type k: int :rtype: int def kth_smallest(self, root, k): """ :type root: TreeNode :type k: int :rtype: int """ count = [] self.helper(root, count) return count[k-1]
:type num: int :rtype: str def int_to_roman(num): """ :type num: int :rtype: str """ m = ["", "M", "MM", "MMM"]; c = ["", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"]; x = ["", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"]; i = ["", "I", "II", "III", "IV", "V", ...
:type input: str :rtype: int def length_longest_path(input): """ :type input: str :rtype: int """ curr_len, max_len = 0, 0 # running length and max length stack = [] # keep track of the name length for s in input.split('\n'): print("---------") print("<path>:", s) ...
:type A: List[List[int]] :type B: List[List[int]] :rtype: List[List[int]] def multiply(self, a, b): """ :type A: List[List[int]] :type B: List[List[int]] :rtype: List[List[int]] """ if a is None or b is None: return None m, n, l = len(a), len(b[0]), len(b[0]) if len(b) != n: ...
:type A: List[List[int]] :type B: List[List[int]] :rtype: List[List[int]] def multiply(self, a, b): """ :type A: List[List[int]] :type B: List[List[int]] :rtype: List[List[int]] """ if a is None or b is None: return None m, n = len(a), len(b[0]) if len(b) != n: raise Exc...
bitonic sort is sorting algorithm to use multiple process, but this code not containing parallel process It can sort only array that sizes power of 2 It can sort array in both increasing order and decreasing order by giving argument true(increasing) and false(decreasing) Worst-case in parallel: O(log(n...
Computes the strongly connected components of a graph def scc(graph): ''' Computes the strongly connected components of a graph ''' order = [] vis = {vertex: False for vertex in graph} graph_transposed = {vertex: [] for vertex in graph} for (v, neighbours) in graph.iteritems(): for u in n...
Builds the implication graph from the formula def build_graph(formula): ''' Builds the implication graph from the formula ''' graph = {} for clause in formula: for (lit, _) in clause: for neg in [False, True]: graph[(lit, neg)] = [] for ((a_lit, a_neg), (b_lit, b_n...
1. Sort all the arrays - a,b,c. - This improves average time complexity. 2. If c[i] < Sum, then look for Sum - c[i] in array a and b. When pair found, insert c[i], a[j] & b[k] into the result list. This can be done in O(n). 3. Keep on doing the above procedure while going through complete c array....
:type root: TreeNode :rtype: bool def is_bst(root): """ :type root: TreeNode :rtype: bool """ stack = [] pre = None while root or stack: while root: stack.append(root) root = root.left root = stack.pop() if pre and root.val <= pre.va...
return 0 if unbalanced else depth + 1 def __get_depth(root): """ return 0 if unbalanced else depth + 1 """ if root is None: return 0 left = __get_depth(root.left) right = __get_depth(root.right) if abs(left-right) > 1 or -1 in [left, right]: return -1 return 1 + max(lef...
:type head: RandomListNode :rtype: RandomListNode def copy_random_pointer_v1(head): """ :type head: RandomListNode :rtype: RandomListNode """ dic = dict() m = n = head while m: dic[m] = RandomListNode(m.label) m = m.next while n: dic[n].next = dic.get(n.next)...
:type head: RandomListNode :rtype: RandomListNode def copy_random_pointer_v2(head): """ :type head: RandomListNode :rtype: RandomListNode """ copy = defaultdict(lambda: RandomListNode(0)) copy[None] = None node = head while node: copy[node].label = node.label copy[no...
[summary] Arguments: n {[int]} -- [to analysed number] Returns: [list of lists] -- [all factors of the number n] def get_factors(n): """[summary] Arguments: n {[int]} -- [to analysed number] Returns: [list of lists] -- [all factors of the number n...
[summary] Computes all factors of n. Translated the function get_factors(...) in a call-stack modell. Arguments: n {[int]} -- [to analysed number] Returns: [list of lists] -- [all factors] def get_factors_iterative1(n): """[summary] Computes all factors of n. Trans...
[summary] analog as above Arguments: n {[int]} -- [description] Returns: [list of lists] -- [all factors of n] def get_factors_iterative2(n): """[summary] analog as above Arguments: n {[int]} -- [description] Returns: [list of lists] -- [all facto...
Dynamic Programming Algorithm for counting the length of longest increasing subsequence type sequence: List[int] def longest_increasing_subsequence(sequence): """ Dynamic Programming Algorithm for counting the length of longest increasing subsequence type sequence: List[int] """ length ...
:type nums: List[int] :rtype: List[int] def single_number3(nums): """ :type nums: List[int] :rtype: List[int] """ # isolate a^b from pairs using XOR ab = 0 for n in nums: ab ^= n # isolate right most bit from a^b right_most = ab & (-ab) # isolate a and b from a^b ...
[summary] HELPER-FUNCTION calculates the (eulidean) distance between vector x and y. Arguments: x {[tuple]} -- [vector] y {[tuple]} -- [vector] def distance(x,y): """[summary] HELPER-FUNCTION calculates the (eulidean) distance between vector x and y. Arguments: x {...
[summary] Implements the nearest neighbor algorithm Arguments: x {[tupel]} -- [vector] tSet {[dict]} -- [training set] Returns: [type] -- [result of the AND-function] def nearest_neighbor(x, tSet): """[summary] Implements the nearest neighbor algorithm Arguments: ...
:type num: str :rtype: bool def is_strobogrammatic(num): """ :type num: str :rtype: bool """ comb = "00 11 88 69 96" i = 0 j = len(num) - 1 while i <= j: x = comb.find(num[i]+num[j]) if x == -1: return False i += 1 j -= 1 return True
Merge Sort Complexity: O(n log(n)) def merge_sort(arr): """ Merge Sort Complexity: O(n log(n)) """ # Our recursive base case if len(arr) <= 1: return arr mid = len(arr) // 2 # Perform merge_sort recursively on both halves left, right = merge_sort(arr[:mid]), merge_so...
Merge helper Complexity: O(n) def merge(left, right, merged): """ Merge helper Complexity: O(n) """ left_cursor, right_cursor = 0, 0 while left_cursor < len(left) and right_cursor < len(right): # Sort each one and place into the result if left[left_cursor] <= right[righ...
Bucket Sort Complexity: O(n^2) The complexity is dominated by nextSort def bucket_sort(arr): ''' Bucket Sort Complexity: O(n^2) The complexity is dominated by nextSort ''' # The number of buckets and make buckets num_buckets = len(arr) buckets = [[] for bucket in ran...
Initialize max heap with first k points. Python does not support a max heap; thus we can use the default min heap where the keys (distance) are negated. def k_closest(points, k, origin=(0, 0)): # Time: O(k+(n-k)logk) # Space: O(k) """Initialize max heap with first k points. Python does not support ...
:type head: ListNode :rtype: ListNode def reverse_list(head): """ :type head: ListNode :rtype: ListNode """ if not head or not head.next: return head prev = None while head: current = head head = head.next current.next = prev prev = current re...
:type head: ListNode :rtype: ListNode def reverse_list_recursive(head): """ :type head: ListNode :rtype: ListNode """ if head is None or head.next is None: return head p = head.next head.next = None revrest = reverse_list_recursive(p) p.next = head return revrest
:type root: TreeNode :type sum: int :rtype: bool def has_path_sum(root, sum): """ :type root: TreeNode :type sum: int :rtype: bool """ if root is None: return False if root.left is None and root.right is None and root.val == sum: return True sum -= root.val r...
:type n: int :type base: int :rtype: str def int_to_base(n, base): """ :type n: int :type base: int :rtype: str """ is_negative = False if n == 0: return '0' elif n < 0: is_negative = True n *= -1 digit = string.digits + string.asc...
Note : You can use int() built-in function instread of this. :type s: str :type base: int :rtype: int def base_to_int(s, base): """ Note : You can use int() built-in function instread of this. :type s: str :type base: int :rtype: int """ digit = ...
:type head: Node :rtype: bool def is_cyclic(head): """ :type head: Node :rtype: bool """ if not head: return False runner = head walker = head while runner.next and runner.next.next: runner = runner.next.next walker = walker.next if runner == walker: ...
:type s: str :rtype: str def decode_string(s): """ :type s: str :rtype: str """ stack = []; cur_num = 0; cur_string = '' for c in s: if c == '[': stack.append((cur_string, cur_num)) cur_string = '' cur_num = 0 elif c == ']': pr...
A slightly more Pythonic approach with a recursive generator def palindromic_substrings_iter(s): """ A slightly more Pythonic approach with a recursive generator """ if not s: yield [] return for i in range(len(s), 0, -1): sub = s[:i] if sub == sub[::-1]: ...
:type s: str :type t: str :rtype: bool def is_isomorphic(s, t): """ :type s: str :type t: str :rtype: bool """ if len(s) != len(t): return False dict = {} set_value = set() for i in range(len(s)): if s[i] not in dict: if t[i] in set_value: ...
Calculate operation result n2 Number: Number 2 n1 Number: Number 1 operator Char: Operation to calculate def calc(n2, n1, operator): """ Calculate operation result n2 Number: Number 2 n1 Number: Number 1 operator Char: Operation to calculate """ if operator == '-':...
Apply operation to the first 2 items of the output queue op_stack Deque (reference) out_stack Deque (reference) def apply_operation(op_stack, out_stack): """ Apply operation to the first 2 items of the output queue op_stack Deque (reference) out_stack Deque (reference) """ o...
Return array of parsed tokens in the expression expression String: Math expression to parse in infix notation def parse(expression): """ Return array of parsed tokens in the expression expression String: Math expression to parse in infix notation """ result = [] current = "" ...
Calculate result of expression expression String: The expression type Type (optional): Number type [int, float] def evaluate(expression): """ Calculate result of expression expression String: The expression type Type (optional): Number type [int, float] """ op_stack = deque...
simple user-interface def main(): """ simple user-interface """ print("\t\tCalculator\n\n") while True: user_input = input("expression or exit: ") if user_input == "exit": break try: print("The result is {0}".format(evaluate(user_input))...
:type root: TreeNode :type target: float :rtype: int def closest_value(root, target): """ :type root: TreeNode :type target: float :rtype: int """ a = root.val kid = root.left if target < a else root.right if not kid: return a b = closest_value(kid, target) retur...
Return list of all primes less than n, Using sieve of Eratosthenes. def get_primes(n): """Return list of all primes less than n, Using sieve of Eratosthenes. """ if n <= 0: raise ValueError("'n' must be a positive integer.") # If x is even, exclude x from list (-1): sieve_size = (n ...
returns a list with the permuations. def permute(elements): """ returns a list with the permuations. """ if len(elements) <= 1: return [elements] else: tmp = [] for perm in permute(elements[1:]): for i in range(len(elements)): tmp.append(perm[...
iterator: returns a perumation by each call. def permute_iter(elements): """ iterator: returns a perumation by each call. """ if len(elements) <= 1: yield elements else: for perm in permute_iter(elements[1:]): for i in range(len(elements)): yield perm...
Extended GCD algorithm. Return s, t, g such that a * s + b * t = GCD(a, b) and s and t are co-prime. def extended_gcd(a, b): """Extended GCD algorithm. Return s, t, g such that a * s + b * t = GCD(a, b) and s and t are co-prime. """ old_s, s = 1, 0 old_t, t = 0, 1 old_r, r ...
type root: root class def bin_tree_to_list(root): """ type root: root class """ if not root: return root root = bin_tree_to_list_util(root) while root.left: root = root.left return root
:type num: str :type target: int :rtype: List[str] def add_operators(num, target): """ :type num: str :type target: int :rtype: List[str] """ def dfs(res, path, num, target, pos, prev, multed): if pos == len(num): if target == prev: res.append(path) ...
internal library initializer. def _init_rabit(): """internal library initializer.""" if _LIB is not None: _LIB.RabitGetRank.restype = ctypes.c_int _LIB.RabitGetWorldSize.restype = ctypes.c_int _LIB.RabitIsDistributed.restype = ctypes.c_int _LIB.RabitVersionNumber.restype = ctype...
Initialize the rabit library with arguments def init(args=None): """Initialize the rabit library with arguments""" if args is None: args = [] arr = (ctypes.c_char_p * len(args))() arr[:] = args _LIB.RabitInit(len(arr), arr)
Print message to the tracker. This function can be used to communicate the information of the progress to the tracker Parameters ---------- msg : str The message to be printed to tracker. def tracker_print(msg): """Print message to the tracker. This function can be used to commun...
Get the processor name. Returns ------- name : str the name of processor(host) def get_processor_name(): """Get the processor name. Returns ------- name : str the name of processor(host) """ mxlen = 256 length = ctypes.c_ulong() buf = ctypes.create_string_b...
Broadcast object from one node to all other nodes. Parameters ---------- data : any type that can be pickled Input data, if current rank does not equal root, this can be None root : int Rank of the node to broadcast data from. Returns ------- object : int the result...
Normalize UNIX path to a native path. def normpath(path): """Normalize UNIX path to a native path.""" normalized = os.path.join(*path.split("/")) if os.path.isabs(path): return os.path.abspath("/") + normalized else: return normalized
internal training function def _train_internal(params, dtrain, num_boost_round=10, evals=(), obj=None, feval=None, xgb_model=None, callbacks=None): """internal training function""" callbacks = [] if callbacks is None else callbacks evals = list(ev...
Train a booster with given parameters. Parameters ---------- params : dict Booster params. dtrain : DMatrix Data to be trained. num_boost_round: int Number of boosting iterations. evals: list of pairs (DMatrix, string) List of items to be evaluated during trainin...
Make an n-fold list of CVPack from random indices. def mknfold(dall, nfold, param, seed, evals=(), fpreproc=None, stratified=False, folds=None, shuffle=True): """ Make an n-fold list of CVPack from random indices. """ evals = list(evals) np.random.seed(seed) if stratified is False ...
Aggregate cross-validation results. If verbose_eval is true, progress is displayed in every call. If verbose_eval is an integer, progress will only be displayed every `verbose_eval` trees, tracked via trial. def aggcv(rlist): # pylint: disable=invalid-name """ Aggregate cross-validation result...
Cross-validation with given parameters. Parameters ---------- params : dict Booster params. dtrain : DMatrix Data to be trained. num_boost_round : int Number of boosting iterations. nfold : int Number of folds in CV. stratified : bool Perform stratifi...
Update the boosters for one iteration def update(self, iteration, fobj): """"Update the boosters for one iteration""" self.bst.update(self.dtrain, iteration, fobj)
Evaluate the CVPack for one iteration. def eval(self, iteration, feval): """"Evaluate the CVPack for one iteration.""" return self.bst.eval_set(self.watchlist, iteration, feval)
return whether the current callback context is cv or train def _get_callback_context(env): """return whether the current callback context is cv or train""" if env.model is not None and env.cvfolds is None: context = 'train' elif env.model is None and env.cvfolds is not None: context = 'cv' ...
format metric string def _fmt_metric(value, show_stdv=True): """format metric string""" if len(value) == 2: return '%s:%g' % (value[0], value[1]) if len(value) == 3: if show_stdv: return '%s:%g+%g' % (value[0], value[1], value[2]) return '%s:%g' % (value[0], value[1]) ...
Create a callback that print evaluation result. We print the evaluation results every **period** iterations and on the first and the last iterations. Parameters ---------- period : int The period to log the evaluation results show_stdv : bool, optional Whether show stdv if pr...
Create a call back that records the evaluation history into **eval_result**. Parameters ---------- eval_result : dict A dictionary to store the evaluation results. Returns ------- callback : function The requested callback function. def record_evaluation(eval_result): """Cr...
Reset learning rate after iteration 1 NOTE: the initial learning rate will still take in-effect on first iteration. Parameters ---------- learning_rates: list or function List of learning rate for each boosting round or a customized function that calculates eta in terms of curr...
Create a callback that activates early stoppping. Validation error needs to decrease at least every **stopping_rounds** round(s) to continue training. Requires at least one item in **evals**. If there's more than one, will use the last. Returns the model from the last iteration (not the best one). ...
Run the doxygen make command in the designated folder. def run_doxygen(folder): """Run the doxygen make command in the designated folder.""" try: retcode = subprocess.call("cd %s; make doxygen" % folder, shell=True) if retcode < 0: sys.stderr.write("doxygen terminated by signal %s" % (-retcode)) ex...
Decorate an objective function Converts an objective function using the typical sklearn metrics signature so that it is usable with ``xgboost.training.train`` Parameters ---------- func: callable Expects a callable with signature ``func(y_true, y_pred)``: y_true: array_like of sha...
Set the parameters of this estimator. Modification of the sklearn method to allow unknown kwargs. This allows using the full range of xgboost parameters that are not defined as member variables in sklearn grid search. Returns ------- self def set_params(self, **params): ...
Get parameters. def get_params(self, deep=False): """Get parameters.""" params = super(XGBModel, self).get_params(deep=deep) if isinstance(self.kwargs, dict): # if kwargs is a dict, update params accordingly params.update(self.kwargs) if params['missing'] is np.nan: ...
Get xgboost type parameters. def get_xgb_params(self): """Get xgboost type parameters.""" xgb_params = self.get_params() random_state = xgb_params.pop('random_state') if 'seed' in xgb_params and xgb_params['seed'] is not None: warnings.warn('The seed parameter is deprecated ...
Load the model from a file. The model is loaded from an XGBoost internal binary format which is universal among the various XGBoost interfaces. Auxiliary attributes of the Python Booster object (such as feature names) will not be loaded. Label encodings (text labels to numeric labels) w...
Fit the gradient boosting model Parameters ---------- X : array_like Feature matrix y : array_like Labels sample_weight : array_like instance weights eval_set : list, optional A list of (X, y) tuple pairs to use as a valida...
Predict with `data`. .. note:: This function is not thread safe. For each booster object, predict can only be called from one thread. If you want to run prediction using multiple thread, call ``xgb.copy()`` to make copies of model object and then call ``predict()``. .. n...
Return the predicted leaf every tree for each sample. Parameters ---------- X : array_like, shape=[n_samples, n_features] Input features matrix. ntree_limit : int Limit number of trees in the prediction; defaults to 0 (use all trees). Returns --...
Feature importances property .. note:: Feature importance is defined only for tree boosters Feature importance is only defined when the decision tree model is chosen as base learner (`booster=gbtree`). It is not defined for other base learner types, such as linear learners ...
Coefficients property .. note:: Coefficients are defined only for linear learners Coefficients are only defined when the linear model is chosen as base learner (`booster=gblinear`). It is not defined for other base learner types, such as tree learners (`booster=gbtree`). ...
Intercept (bias) property .. note:: Intercept is defined only for linear learners Intercept (bias) is only defined when the linear model is chosen as base learner (`booster=gblinear`). It is not defined for other base learner types, such as tree learners (`booster=gbtree`)....
Fit gradient boosting classifier Parameters ---------- X : array_like Feature matrix y : array_like Labels sample_weight : array_like Weight for each instance eval_set : list, optional A list of (X, y) pairs to use as a val...
Predict with `data`. .. note:: This function is not thread safe. For each booster object, predict can only be called from one thread. If you want to run prediction using multiple thread, call ``xgb.copy()`` to make copies of model object and then call ``predict()``. .. n...
Predict the probability of each `data` example being of a given class. .. note:: This function is not thread safe For each booster object, predict can only be called from one thread. If you want to run prediction using multiple thread, call ``xgb.copy()`` to make copies of ...
Fit the gradient boosting model Parameters ---------- X : array_like Feature matrix y : array_like Labels group : array_like group size of training data sample_weight : array_like group weights .. note:: Weight...
Convert a list of Python str to C pointer Parameters ---------- data : list list of str def from_pystr_to_cstr(data): """Convert a list of Python str to C pointer Parameters ---------- data : list list of str """ if not isinstance(data, list): raise NotImp...
Revert C pointer to Python str Parameters ---------- data : ctypes pointer pointer to data length : ctypes pointer pointer to length of data def from_cstr_to_pystr(data, length): """Revert C pointer to Python str Parameters ---------- data : ctypes pointer poin...
Load xgboost Library. def _load_lib(): """Load xgboost Library.""" lib_paths = find_lib_path() if not lib_paths: return None try: pathBackup = os.environ['PATH'].split(os.pathsep) except KeyError: pathBackup = [] lib_success = False os_error_list = [] for lib_pat...
Convert a ctypes pointer array to a numpy array. def ctypes2numpy(cptr, length, dtype): """Convert a ctypes pointer array to a numpy array. """ NUMPY_TO_CTYPES_MAPPING = { np.float32: ctypes.c_float, np.uint32: ctypes.c_uint, } if dtype not in NUMPY_TO_CTYPES_MAPPING: raise ...
Convert ctypes pointer to buffer type. def ctypes2buffer(cptr, length): """Convert ctypes pointer to buffer type.""" if not isinstance(cptr, ctypes.POINTER(ctypes.c_char)): raise RuntimeError('expected char pointer') res = bytearray(length) rptr = (ctypes.c_char * length).from_buffer(res) i...
Convert a python string to c array. def c_array(ctype, values): """Convert a python string to c array.""" if isinstance(values, np.ndarray) and values.dtype.itemsize == ctypes.sizeof(ctype): return (ctype * len(values)).from_buffer_copy(values) return (ctype * len(values))(*values)
Extract internal data from pd.DataFrame for DMatrix data def _maybe_pandas_data(data, feature_names, feature_types): """ Extract internal data from pd.DataFrame for DMatrix data """ if not isinstance(data, DataFrame): return data, feature_names, feature_types data_dtypes = data.dtypes if not ...
Validate feature names and types if data table def _maybe_dt_data(data, feature_names, feature_types): """ Validate feature names and types if data table """ if not isinstance(data, DataTable): return data, feature_names, feature_types data_types_names = tuple(lt.name for lt in data.ltypes...