xinyu04

摘要： There is an integer array nums sorted in ascending order (with distinct values). Prior to being passed to your function, nums is possibly rotated at a 阅读全文

摘要： Given an array of integers `nums` sorted in non-decreasing order, find the starting and ending position of a given target value. If target is not foun 阅读全文

摘要： Reverse bits of a given 32 bits unsigned integer. Input: n = 11111111111111111111111111111101 Output: 3221225471 (10111111111111111111111111111111) Ex 阅读全文

摘要： Given the root of a binary tree, return the zigzag level order traversal of its nodes' values. (i.e., from left to right, then right to left for the n 阅读全文

摘要： Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center). Solution 判断树是否为对称的。我们可以直接对左右子树进行 $DFS$ 递归 阅读全文

摘要： Given $n$ pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Input: n = 3 Output: ["((()))","(()())","(() 阅读全文

摘要： 1. B problem B 每次删除两个元素，问最后可以保留的最大的序列长度：满足序列中每个元素都不相同。 思路： 用 $map$ 来统计一下数字出现的次数。我们接着记录奇数次数以及偶数次数的个数，次数为奇数的显然可以全部保留，对于偶数的 $-1$ 点击查看代码 #include<iostream 阅读全文

摘要： Given an array of points where points[i] = [xi, yi] represents a point on the $X-Y$ plane, return the maximum number of points that lie on the same st 阅读全文

摘要： Given a string s, you can transform every letter individually to be lowercase or uppercase to create another string. Return a list of all possible str 阅读全文

摘要： Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order. Solution 我们需要求出一个数组的全排列。那么还是依旧 阅读全文