leetcode 698. Partition to K Equal Sum Subsets

题目链接：698. Partition to K Equal Sum Subsets
等级： medium

思路

直接使用dfs深搜，深搜过程中，记录以及匹配完全的子集合个数，以及深搜当前状态下的和等

实现

# include <iostream># include <vector>using namespace std;/*Given an array of integers nums and a positive integer k, find whether it's possible to divide this array into k non-empty subsets whose sums are all equal.Example 1:Input: nums = [4, 3, 2, 3, 5, 2, 1], k = 4Output: TrueExplanation: It's possible to divide it into 4 subsets (5), (1, 4), (2,3), (2,3) with equal sums.Note:1 <= k <= len(nums) <= 16.0 < nums[i] < 10000. */class Solution {public:  vector<bool> visited;  bool canPartitionKSubsets(vector<int>& nums, int k) {    if(k == 1) return true;    int sum = 0, size = nums.size();    for(int i = 0; i < size; i++) sum += nums[i];    if(sum % k) return false;    this->visited = vector<bool>(size, false);    return this->dfs(nums, 0, k, 0, sum / k);  }  bool dfs(vector<int> & nums, int index, int k, int c_sum, int target) {    if(k == 1) return true;    if(c_sum == target) return this->dfs(nums, 0, k - 1, 0, target);    int size = nums.size();    for(int i = index; i < size; i++) if(this->visited[i] == false){      this->visited[i] = true;      if(this->dfs(nums, i + 1, k, c_sum + nums[i], target)) return true;      this->visited[i] = false;    }    return false;  }};int main() {  int a [] = {2, 2, 10, 5, 2, 7, 2, 2, 13};  vector<int> nums(a, a + 9);  Solution so;  cout << so.canPartitionKSubsets(nums, 3) << endl;}