PartitiontoKEqualSumSubsets问题及解法

问题描述：

Given an array of integers nums and a positive integer k, find whether it&＃39;s possible to divide this array into k non-empty subsets whose sums are all equal.

示例:

Input: nums = [4, 3, 2, 3, 5, 2, 1], k = 4
Output: True
Explanation: It&＃39;s possible to divide it into 4 subsets (5), (1, 4), (2,3), (2,3) with equal sums.

问题分析：

可以先求出数组和sum，看看是否能整除k，若不能，返回false，否则，遍历整个数组，看看是否能划分成k个子序列和相等的分割。

注意，这里对数组进行了降序排序。

过程详见代码：

class Solution {
public:bool canPartitionKSubsets(vector& nums, int k) {int sum = accumulate(nums.begin(), nums.end(), 0);sort(nums.begin(), nums.end(), [](int a, int b){return a > b; });if (sum % k) return false;int t = sum / k;vector dp(nums.size(), false);int res = 0;for (int i = 0; i & dp, vector& nums, int target, int start,int sum){if (sum == target) {return true;}for (int i = start; i };