人生苦短，我用Python
An array is monotonic if it is either monotone increasing or monotone decreasing.
An array A is monotone increasing if for all i <= j, A[i] <= A[j]. An array A is monotone decreasing if for all i <= j, A[i] >= A[j].
Return true if and only if the given array A is monotonic.
题目链接：https://leetcode.com/problems/monotonic-array/description/
给定一个数组A[0,1,…,n-1],请构建一个数组B[0,1,…,n-1],其中B中的元素B[i]=A[0]A[1]…A[i-1]A[i+1]…A[n-1]。不能使用除法。
题目链接： https://www.nowcoder.com/practice/94a4d381a68b47b7a8bed86f2975db46
在一个长度为n的数组里的所有数字都在0到n-1的范围内。 数组中某些数字是重复的，但不知道有几个数字是重复的。也不知道每个数字重复几次。请找出数组中任意一个重复的数字。 例如，如果输入长度为7的数组{2,3,1,0,2,5,3}，那么对应的输出是第一个重复的数字2。
题目链接： https://www.nowcoder.com/practice/623a5ac0ea5b4e5f95552655361ae0a8
将一个字符串转换成一个整数(实现Integer.valueOf(string)的功能，但是string不符合数字要求时返回0)，要求不能使用字符串转换整数的库函数。 数值为0或者字符串不是一个合法的数值则返回0。
题目链接： https://www.nowcoder.com/practice/1277c681251b4372bdef344468e4f26e
写一个函数，求两个整数之和，要求在函数体内不得使用+、-、*、/四则运算符号。
题目链接： https://www.nowcoder.com/practice/59ac416b4b944300b617d4f7f111b215
求1+2+3+…+n，要求不能使用乘除法、for、while、if、else、switch、case等关键字及条件判断语句（A?B:C）。
题目链接： https://www.nowcoder.com/practice/7a0da8fc483247ff8800059e12d7caf1
Implement FreqStack, a class which simulates the operation of a stack-like data structure.
FreqStack has two functions:
push(int x), which pushes an integer x onto the stack.
pop(), which removes and returns the most frequent element in the stack.
If there is a tie for most frequent element, the element closest to the top of the stack is removed and returned.
题目链接：https://leetcode.com/problems/maximum-frequency-stack/description/
A full binary tree is a binary tree where each node has exactly 0 or 2 children.
Return a list of all possible full binary trees with N nodes. Each element of the answer is the root node of one possible tree.
Each node of each tree in the answer must have node.val = 0.
You may return the final list of trees in any order.
题目链接：https://leetcode.com/problems/all-possible-full-binary-trees/description/
You are given an array A of strings.
Two strings S and T are special-equivalent if after any number of moves, S == T.
A move consists of choosing two indices i and j with i % 2 == j % 2, and swapping S[i] with S[j].
Now, a group of special-equivalent strings from A is a non-empty subset S of A such that any string not in S is not special-equivalent with any string in S.
Return the number of groups of special-equivalent strings from A.
题目链接：https://leetcode.com/problems/groups-of-special-equivalent-strings/description/
On a N N grid, we place some 1 1 * 1 cubes.
Each value v = grid[i][j] represents a tower of v cubes placed on top of grid cell (i, j).
Return the total surface area of the resulting shapes.
题目链接：https://leetcode.com/problems/surface-area-of-3d-shapes/description/