leetcode Trapping Rain Water
Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.
For example, Given
[0,1,0,2,1,0,1,3,2,1,2,1], return6.
The above elevation map is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped. Thanks Marcos for contributing this image!
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]return3, and[3,4,-1,1]return2.Your algorithm should run in O(n) time and uses constant space.
leetcode 全排列详解
本文为leetcode 全排列的详解，包括：
- 31 Next Permutation
- 46 Permutations
- 47 Permutations II
- 60 Permutation Sequence
leetcode 55 Jump Game || 45 Jump Game II
leetcode 38 Count and Say
The count-and-say sequence is the sequence of integers beginning as follows:
1, 11, 21, 1211, 111221, ...
1is read off as"one 1"or11.11is read off as"two 1s"or21.21is read off as"one 2, thenone 1"or1211.Given an integer n, generate the _n_th sequence.
Note: The sequence of integers will be represented as a string.
leetcode 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.