Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. 这道题是之前那道Permutations 全排列的延伸,由于输入数组有可能出现重复数字,如果按照之前的算法运算,会有…
Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…
Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm? Hint: Expected runtime complexity is in O(log n) and the input is sorted. 这题是之前那道H-Index 求H指数的拓展,输入数组是有序的,让我们在O(log n)的时间内完成计算,看到这个时间复…
Given a collection of integers that might contain duplicates, S, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. For example,If S = [1,2,2], a solution is:…
Follow up for N-Queens problem. Now, instead outputting board configurations, return the total number of distinct solutions. 这道题是之前那道N-Queens N皇后问题 的延伸,说是延伸其实我觉得两者顺序应该颠倒一样,上一道题比这道题还要稍稍复杂一些,两者本质上没有啥区别,都是要用回溯法Backtracking来解,如果理解了之前那道题的思路,此题只要做很小的改动即可,不…
原题链接在这里:https://leetcode.com/problems/h-index-ii/ 题目: Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm? 题解: 与H-Index类似.已经排好序,直接二分法查找即可. Time Complexity: O(logn). Space: O(1). AC Java:…
Follow up for N-Queens problem. Now, instead outputting board configurations, return the total number of distinct solutions. 原题链接:https://oj.leetcode.com/problems/n-queens-ii/ 题目:求有多少个独立的解决方式. 与上题一致,仅仅要每次成功后记录一下次数就可以. package leetcode; import java.ut…
原题地址:https://oj.leetcode.com/problems/permutations-ii/ 题意: Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1].…
原题地址:https://oj.leetcode.com/problems/subsets-ii/ 题意: Given a collection of integers that might contain duplicates, S, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicat…
Permutations II Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. SOLUTION 1: 还是经典的递归模板.需要处理的情况是:我们先把Num排序,然…
Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. 解题思路: Permutations 那题输入是不包含重复元素的,故生成的排列都是不同的,II中输入元素可能相同 因…
https://oj.leetcode.com/problems/n-queens-ii/ N皇后问题,计算解的个数 class Solution { public: int totalNQueens(int n) { ) ; vector<); ; placeQueen(, n, ans, places); return ans; } // col and lines bool valid(int i, int j, vector<int> &places) { ; p<…
Follow up for N-Queens problem. Now, instead outputting board configurations, return the total number of distinct solutions. class Solution { public: int totalNQueens(int n) { vector<); ; i < n; ++ i) queen[i] = i; ; do{ bool flag = false; ; i <…
Given a collection of integers that might contain duplicates, S, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. For example,If S = [1,2,2], a solution is:…
Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. Solution: public class Solution { public List<List<Intege…
Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…
Description: 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. 分析:这道题目跟之前的UniquePath基本都是一样的,只是在格子…
题目 Given a collection of integers that might contain duplicates, S, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. For example, If S = [1,2,2], a solution…
Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2]have the following unique permutations:[1,1,2],[1,2,1], and[2,1,1]. 题意:当数列中有重复数字时,求其全排列. 思路:和permutation一样.以[1,1,2]为例,以第一个1为开始,得到…
Given a collection of integers that might contain duplicates, S, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. For example,If S =[1,2,2], a solution is: […
Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. Show Tags Backtracking 这个就是输入一个数组,可能有重复,输出全部的排列. …
