Given a set of candidate numbers (C) (without duplicates) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.
The same repeated number may be chosen from C unlimited number of times.
* Total Accepted: **106670** * Total Submissions: **329718** * Difficulty: **Medium** * Contributor: **LeetCode** Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.
In LLP world, there is a hero called Teemo and his attacking can make his enemy Ashe be in poisoned condition. Now, given the Teemo’s attacking ascending time series towards Ashe and the poisoning time duration per Teemo’s attacking, you need to output the total time that Ashe is in poisoned condition.
Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.
Find all the elements that appear twice in this array.
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?
题意：给一个n*n的方阵，要求顺时针旋转90度。
Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.
思路：。。。再次让我回想起高一的暑假。。。。
Given a collection of intervals, merge all overlapping intervals.
For example, Given [1,3],[2,6],[8,10],[15,18], return [1,6],[8,10],[15,18].
思路:dp[i]表示能否到达位置i…无脑dp即可。。。
Given a collection of intervals, merge all overlapping intervals.
For example, Given [1,3],[2,6],[8,10],[15,18], return [1,6],[8,10],[15,18].
思路：扫一遍即可。。
1/* *********************************************** 2Author :111qqz 3Created Time :2017年04月11日 星期二 19时15分30秒 4File Name :56.cpp 5************************************************ */ 6/** 7 8 * Definition for an interval. 9 10 * struct Interval { 11 12 * int start; 13 14 * int end; 15 16 * Interval() : start(0), end(0) {} 17 18 * Interval(int s, int e) : start(s), end(e) {} 19 20 * }; 21 22 */ 23 24class Solution { 25 26public: 27 28 int n; 29 static bool cmp(Interval A,Interval B) 30 { 31 return A.start<B.start; 32 } 33 vector<Interval> merge(vector<Interval>& pi) { 34 vector<Interval>res; 35 n = pi.size(); 36 if (n==0) return res; 37 sort(pi.begin(),pi.end(),cmp); 38 int l = -1,r = -1; 39 for ( int i = 0 ; i < n ; i++) 40 { 41 if (l==-1&&r==-1) 42 { 43 l = pi[0].start; 44 r = pi[0].end; 45 continue; 46 } 47 if (pi[i].start<=r) 48 { 49 r = max(r,pi[i].end); 50 continue; 51 } 52 if (pi[i].start>r) 53 { 54 res.push_back(Interval(l,r)); 55 l = pi[i].start; 56 r = pi[i].end; 57 continue; 58 } 59 } 60 //最后一组不要忘记 61 res.push_back(Interval(l,r)); 62 int siz = res.size(); 63 for ( int i = 0 ; i < siz ;i++) printf("%d ",res[i].start,res[i].end); 64 65 66 return res; 67 68 } 69 70};
Given an integer n, generate a square matrix filled with elements from 1 to _n_2 in spiral order.
思路：仿佛回到高一的那个暑假。。。
Follow up for “Unique Paths”:
Now consider if some obstacles are added to the grids. How many unique paths would there be?
An obstacle and empty space is marked as 1 and 0 respectively in the grid.
Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.
Note: You can only move either down or right at any point in time.
Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.
click to show follow up.
**Follow up:**Did you use extra space? A straight forward solution using O(m__n) space is probably a bad idea. A simple improvement uses O(m + n) space, but still not the best solution. Could you devise a constant space solution?
Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].
Given a 2D board and a word, find if the word exists in the grid.
The word can be constructed from letters of sequentially adjacent cell, where “adjacent” cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once.
Follow up for “Remove Duplicates”: What if duplicates are allowed at most twice?
For example, Given sorted array nums = [1,1,1,2,2,3],
Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3. It doesn’t matter what you leave beyond the new length.
Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.
(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).
According to the Wikipedia’s article: “The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970.”
Given a board with m by n cells, each cell has an initial state live (1) or dead (0). Each cell interacts with its eight neighbors (horizontal, vertical, diagonal) using the following four rules (taken from the above Wikipedia article):
Given a collection of integers that might contain duplicates, nums, return all possible subsets.
Note: The solution set must not contain duplicate subsets.
For example, If nums = [1,2,2], a solution is:
/* ***********************************************
1Author :111qqz 2Created Time :2017年04月05日 星期三 16时49分57秒 3File Name :106.cpp 4************************************************ */ 5/** 6 * Definition for a binary tree node. 7 * struct TreeNode { 8 * int val; 9 * TreeNode *left; 10 * TreeNode *right; 11 * TreeNode(int x) : val(x), left(NULL), right(NULL) {} 12 * }; 13 */ 14class Solution { 15public: 16 TreeNode* buildTree(vector<int>& inorder, vector<int>& postorder) { 17 int siz = inorder.size(); 18 if (siz==0) return NULL; 19 int rt = postorder[siz-1]; 20 int pos = -1; 21 for ( int i = 0 ; i < siz; i++) 22 { 23 if (inorder[i]==rt) 24 { 25 pos = i ; 26 break; 27 } 28 } 29 TreeNode *head = new TreeNode(rt); 30 vector<int>in,post; 31 for ( int i = 0 ; i < pos ; i++) 32 { 33 in.push_back(inorder[i]); 34 post.push_back(postorder[i]); 35 } 36 head->left = buildTree(in,post); 37 in.clear(); 38 post.clear(); 39 for ( int i = pos + 1 ; i < siz ; i++) 40 { 41 in.push_back(inorder[i]); 42 post.push_back(postorder[i-1]); 43 } 44 head->right = buildTree(in,post); 45 return head; 46 } 47};
Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, find the duplicate one.
