78. Subsets Given a set of distinct integers, nums, return all possible subsets. Note: The solution set must not contain duplicate subsets. For example, If nums = [,,], a solution is: [ [], [], [], [,,], [,], [,], [,], [] ] class Solution { public: v…

第一题是输入数组的数值不相同,第二题是输入数组的数值有相同的值,第二题在第一题的基础上需要过滤掉那些相同的数值. level代表的是需要进行选择的数值的位置. 78. Subsets 错误解法: class Solution { public: vector<vector<int>> subsets(vector<int>& nums) { vector<vector<int> > result; if(nums.empty()) ret…

一.题目说明 题目78. Subsets,给一列整数,求所有可能的子集.题目难度是Medium! 二.我的解答 这个题目,前面做过一个类似的,相当于求闭包: 刷题22. Generate Parentheses 算了,用最简单的回溯法吧: class Solution{ public: void dfs(vector<int>& nums,int start){ r.push_back(path); for(int i=start;i<len;i++){ path.push_ba…

Given a set of distinct integers, 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 = [1,2,3], a solution is: [ [3], [1], [2], [1,2,3], [1…

原题地址 有两种方法: 1. 对于序列S,其子集可以对应为一个二进制数,每一位对应集合中的某个数字,0代表不选,1代表选,比如S={1,2,3},则子集合就是3bit的所有二进制数. 所以,照着二进制位去构造解空间即可. 2. 也可以用DFS做,对于每个元素,要么选,要么不选. 记得先排序,因为结果集的数字要从小到大出现. 代码(DFS版本): vector<vector<int> > res; void dfs(vector<int> &S, vector&l…

题目: Given a set of distinct integers, 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 = [1,2,3], a solution is: [ [3], [1], [2], [1,2,3]…

题目意思:求解一个数组的所有子集,子集内的元素增序排列eg:[1,3,2] result:[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]思路:这是一个递推的过程 [] []+[1] [2]+[1,2]+[]+[1] 第k项的子集为第k个数分别加到k-1项的子集,再加上k-1项的子集程序过程:------------------- ans[0] []------------------- ans[1] [1]------------------- ans[2] […

Given a set of distinct integers, nums, 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 nums = [1,2,3], a solution is: [ [3], [1], [2], [1,2…

Given a set of distinct integers, nums, return all possible subsets. Note: The solution set must not contain duplicate subsets. For example,If nums = [1,2,3], a solution is: [ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ] 题目标签:Array 方法 1: 题目给了我们一…

Given a set of distinct integers, nums, return all possible subsets. Note: The solution set must not contain duplicate subsets. For example, If nums = [1,2,3], a solution is: [ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ] 就是求指定集合的所有子集． 三种解法: Rec…