开先哥哥-CSDN博客

原创 leetcode 题型数据结构解法分类总结

leetcode 题型数据结构解法分类总结

2014-07-08 16:42:16 2239

原创 leetcode: Permutations I II

vector > res; sort(num.begin(), num.end()); res.push_back(num); if(num.size() < 2){ return res; } while(true){ int i = num.size()

2015-04-19 21:01:56 363

原创 leetcode: regular expression match

太丑bool isMatch(string s, string p) { vector > dp(s.size() + 1, vector(p.size() + 1, false)); dp[0][0] = true; for( int i = 1; i <= p.size(); ++i) dp[0][i] = '*' ==

2015-04-17 19:44:21 395

转载 leetcode: Distinct Subsequences

class Solution {public: int numDistinct(string S, string T) { if( S.size() == 0 || S.size() < T.size()) return 0; if( T.size() == 0) return 1; vect

2014-07-11 15:56:54 453

原创 leetcode: Longest Substring Without Repeating Characters

class Solution {public: int lengthOfLongestSubstring(string s) { int used[256]; memset( used, 0, sizeof(used)); int tmp = 0, maximum = 0; for( int i = 0; i < s.siz

2014-07-11 15:00:56 460

原创 leetcode: Minimum Depth of Binary Tree

必须是到叶节点/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */cla

2014-07-11 11:35:18 445

原创 leetcode: Roman to Integer

Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.class Solution {public: int romanToInt(string s) { unordered_map mapping;

2014-07-11 11:14:18 363

原创 leetcode: Integer to Roman

把关键的数字找出来，分别是和1，4，5，9相关的class Solution {public: string intToRoman(int num) { const int integer[] = { 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1}; const string roman[]

2014-07-11 10:45:10 384

原创 leetcode: Search in Rotated Sorted Array II

Follow up for "Search in Rotated Sorted Array":What if duplicates are allowed?Would this affect the run-time complexity? How and why?Write a function to determine if a given target is in the

2014-07-10 22:55:18 391

原创 leetcode: Search a 2D Matrix

杨氏矩阵，对比右上角的数值和目标值daclass Solution {public: bool searchMatrix(vector > &matrix, int target) { if( matrix.size() == 0) return false; int i = 0, j = matrix[0].size() -

2014-07-10 22:01:04 373

原创 leetcode: Set Matrix Zeroes

Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.class Solution {public: void setZeroes(vector > &matrix) { vector > tmp; for(

2014-07-10 21:46:17 470

原创 leetcode: Maximum Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.For example, given the array [−2,1,−3,4,−1,2,1,−5,4],the contiguous subarray [4,−1,2,1] ha

2014-07-10 21:28:33 377

原创 leetcode: Binary Tree Level Order Traversal II

Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For example:Given binary tree {3,9,20,#,#,15,7},

2014-07-10 21:19:09 402

原创 leetcode: Binary Tree Level Order Traversal

Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level).For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20

2014-07-10 21:07:56 349

原创 leetcode: Reverse Linked List II

递归/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {public: ListNode

2014-07-10 14:12:19 415

转载 leetcode: Gas Station

There are N gas stations along a circular route, where the amount of gas at station i is gas[i].You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from station i to

2014-07-09 23:03:04 428

原创 leetcode: Linked List Cycle II

注意两个测试用例，{}/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {public:

2014-07-09 22:40:40 473 1

原创 leetcode: Generate Parentheses

括号匹配种数的问题，其实就是卡特兰数class Solution {public: vector generateParenthesis(int n) { vector res; if( n == 0) return res; core( res, "", n, 0, 0); return res

2014-07-09 22:25:57 406

转载 leetcode: Single Number II

Given an array of integers, every element appears three times except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without usi

2014-07-09 22:09:06 426

原创 leetcode: Search Insert Position

看清题目，插入位置，不是二分查找class Solution {public: int searchInsert(int A[], int n, int target) { if( n == 0) return 0; return binarySearch( A, target, 0, n-1); } int b

2014-07-09 19:40:25 411

原创 leetcode: Pascal's Triangle II

要求只能用O(k)空间，所以用liangclass Solution {public: vector getRow(int rowIndex) { vector > dp( 2, vector( rowIndex+1, 0)); int cur = 1; int pre = 0; dp[pre][0] = 1;

2014-07-09 00:15:19 385

原创 leetcode: Populating Next Right Pointers in Each Node II

Follow up for problem "Populating Next Right Pointers in Each Node".What if the given tree could be any binary tree? Would your previous solution still work?Note:You may only use constant

2014-07-08 23:19:18 538

原创 leetcode: Populating Next Right Pointers in Each Node

Given a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }Populate each next pointer to point to its next right node.

2014-07-08 22:53:32 462

原创 leetcode: Container With Most Water

贪心，最大class Solution {public: int maxArea(vector &height) { if( height.size() < 2) return 0; int res = INT_MIN; int i = 0, j = height.size()-1; while(

2014-07-08 15:28:47 440

原创 leetcode: Trapping Rain Water

先计算每个格的class Solution {public: int trap(int A[], int n) { if( n < 3) return 0; int *max_left = new int[n](); int *max_right = new int[n](); max_left[

2014-07-08 11:29:55 331

转载 leetcode: Largest Rectangle in Histogram

http://blog.csdn.net/doc_sgl/article/details/11805519这篇分析写得heclass Solution {public: int largestRectangleArea(vector &height) { stack stk; height.push_back(0); int r

2014-07-08 10:40:35 323

原创 leetcode: Spiral Matrix

注意各个边界条件，i，j的++，--class Solution {public: vector spiralOrder(vector > &matrix) { vector res; if( matrix.size() == 0) return res; int m = matrix[0].size();

2014-07-07 21:20:58 274

原创 leetcode: Merge k Sorted Lists

多路链表归并，复杂度O(mn log)/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {pub

2014-07-07 20:34:03 387

原创 leetcode: Merge Sorted Array

Given two sorted integer arrays A and B, merge B into A as one sorted array.Note:You may assume that A has enough space (size that is greater or equal to m + n) to hold additional elements from

2014-07-07 20:21:23 378

原创 leetcode: Sort List

Sort a linked list in O(n log n) time using constant space complexity.利用链表归并排序/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListN

2014-07-07 19:57:16 327

原创 leetcode: Restore IP Addresses

DFS、回溯class Solution {public: vector restoreIpAddresses(string s) { vector res; if( s.size() 12) return res; core( res, s, 0, ""); return res;

2014-07-07 17:36:47 473

原创 leetcode: Balanced Binary Tree

/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Soluti

2014-07-06 20:56:45 298

转载 leetcode: Regular Expression Matching

对于S[i]和P[j]：如果P[j+1]!='*'，S[i] == P[j]=>匹配下一位(i+1, j+1)，S[i]!=P[j]=>匹配失败；如果P[j+1]=='*'，S[i]==P[j]=>匹配下一位(i+1, j+2)或者(i, j+2)，S[i]!=P[j]=>匹配下一位(i,j+2)。匹配成功的条件为S[i]=='\0' && P[j]=='\0'。

2014-07-06 18:19:56 409

原创 leetcode: Word Search

深度搜索，挨个搜索每个格子的四个角，符合条件就退出，zhe'lclass Solution {public: bool exist(vector > &board, string word) { if( word == "") return true; for( int i = 0; i < board.size(); ++i)

2014-07-06 17:03:53 375

转载 leetcode:Longest Valid Parentheses

Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.For "(()", the longest valid parentheses substring is "()",

2014-07-06 15:54:48 384

原创 leetcode: Substring with Concatenation of All Words

提交了好多遍，注意每个词搜索class Solution {public: vector findSubstring(string S, vector &L) { vector res; const int word_length = L[0].size(); const int words_length = word_length *

2014-07-05 21:44:04 362

原创 leetcode: Remove Duplicates from Sorted List II

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.For example,Given 1->2->3->3->4->4->5, return 1->2->5.Given 1->1-

2014-07-05 19:08:35 366

原创 leetcode: Remove Duplicates from Sorted Array II

class Solution {public: int removeDuplicates(int A[], int n) { if( n < 2) return n; int cnt = 0; int cur = INT_MIN; int allow = 1; for( int i =

2014-07-05 18:16:40 321

原创 leetcode: Remove Duplicates from Sorted Array

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.Do not allocate extra space for another array, you must do this in place with

2014-07-05 17:51:38 319

原创 leetcode: String to Integer (atoi)

Implement atoi to convert a string to an integer.Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input ca

2014-07-05 17:17:31 357

空空如也

空空如也