crystal_tyan

import random#warning: x and y confusingsx = 10sy = 10dfs = [[0 for col in range(sx)] for row in range(sy)]maze = [[' ' for col in range(2*sx+1)] for row in range(2*sy+1)]#1:up 2:down 3:left 4

OJ's undirected graph serialization:Nodes are labeled uniquely.We use # as a separator for each node, and , as a separator for node label and each neighbor of the node.As an example, consider th

有这样一道OJYou are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?https://oj.leetcode.c

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.push(x) -- Push element x onto stack.pop() -- Removes the element on top of the stack.top() -- Get

Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only nodes with keys less than the node's key.The