## leetcode Rotate Image

### leetcode Rotate Image

You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Follow up: Could you do this in-place?

## leetcode First Missing Positive

Given an unsorted integer array, find the first missing positive integer.

For example,
Given `[1,2,0]` return `3`,
and `[3,4,-1,1]` return `2`.

Your algorithm should run in O(n) time and uses constant space.

## leetcode 全排列详解

• 31 Next Permutation
• 46 Permutations
• 47 Permutations II
• 60 Permutation Sequence

## leetcode 55 Jump Game || 45 Jump Game II

• 45. Jump Game II
• 55. Jump Game

## leetcode 38 Count and Say

The count-and-say sequence is the sequence of integers beginning as follows:
`1, 11, 21, 1211, 111221, ...`

`1` is read off as `"one 1"` or `11`.
`11` is read off as `"two 1s"` or `21`.
`21` is read off as `"one 2`, then `one 1"` or `1211`.

Given an integer n, generate the nth sequence.

Note: The sequence of integers will be represented as a string.

## leetcode 36. Valid Sudoku || 37. Sudoku Solver

• 36. Valid Sudoku
• 37. Sudoku Solver

## leetcode 32 Longest Valid Parentheses

Given a string containing just the characters ‘(‘ and ‘)’, find the length of the longest valid (well-formed) parentheses substring.

Example 1:

Input: “(()”
Output: 2
Explanation: The longest valid parentheses substring is “()”

Example 2:

Input: “)()())”
Output: 4
Explanation: The longest valid parentheses substring is “()()”

## leetcode 30 Substring with Concatenation of All Words

You are given a string, S, and a list of words, L, that are all of the same length. Find all starting indices of substring(s) in S that is a concatenation of each word in L exactly once and without any intervening characters.

For example, given:
S: `"barfoothefoobarman"`
L: `["foo", "bar"]`

You should return the indices: `[0,9]`.
(order does not matter).

## leetcode 29 Divide Two Integers

Divide two integers without using multiplication, division and mod operator.

If it is overflow, return MAX_INT.

## leetcode 11 Container With Most Water

Given n non-negative integers a1, a2, …, an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a container, such that the container contains the most water.

Note: You may not slant the container.