题目

You are given two strings s and t of the same length. You want to change s to t. Changing the i-th character of s to i-th character of t costs |s[i] - t[i]| that is, the absolute difference between the ASCII values of the characters.

You are also given an integer maxCost.

Return the maximum length of a substring of s that can be changed to be the same as the corresponding substring of twith a cost less than or equal to maxCost.

If there is no substring from s that can be changed to its corresponding substring from t, return 0.

题目

一个整型数组 nums 里除两个数字之外，其他数字都出现了两次。请写程序找出这两个只出现一次的数字。要求时间复杂度是O(n)，空间复杂度是O(1)。

示例 1：

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输入：nums = [4,1,4,6]
输出：[1,6] 或 [6,1]

示例 2：

题目

Given an integer n, return the number of trailing zeroes in n!.

Example 1:

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Input: 3
Output: 0
Explanation: 3! = 6, no trailing zero.

Example 2:

题目

The i-th person has weight people[i], and each boat can carry a maximum weight of limit.

Each boat carries at most 2 people at the same time, provided the sum of the weight of those people is at most limit.

Return the minimum number of boats to carry every given person. (It is guaranteed each person can be carried by a boat.)

Example 1:

题目

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

Example:

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Input: \[-2,1,-3,4,-1,2,1,-5,4\],
Output: 6
Explanation: \[4,-1,2,1\] has the largest sum = 6.

Follow up:

题目

Tic-tac-toe is played by two players A and B on a 3 x 3 grid.

Here are the rules of Tic-Tac-Toe:

• Players take turns placing characters into empty squares (" ").
• The first player A always places "X" characters, while the second player B always places "O" characters.
• "X" and "O" characters are always placed into empty squares, never on filled ones.
• The game ends when there are 3 of the same (non-empty) character filling any row, column, or diagonal.
• The game also ends if all squares are non-empty.
• No more moves can be played if the game is over.

Given an array moves where each element is another array of size 2 corresponding to the row and column of the grid where they mark their respective character in the order in which A and B play.

题目

Invert a binary tree.

Example:

Input:

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     4
   /   \
  2     7
 / \   / \
1   3 6   9

Tips:禁用复制限制及复制小尾巴

复制csdn以及LeetCode会有小尾巴而且会破坏原格式，再次手工处理很不方便

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[...document.querySelectorAll('*')].forEach(item=>{
    item.oncopy = function(e) {
        e.stopPropagation();
    }
});

配合油猴使用效果更佳

匹配规则：

*blog.csdn.net/*

*leetcode-cn.com/*

题目

Given an array nums and a value val, remove all instances of that value in-place and return the new length.

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

The order of elements can be changed. It doesn't matter what you leave beyond the new length.

Example 1:

题目

Write an algorithm to determine if a number n is "happy".

A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.

Return True if n is a happy number, and False if not.

Example: