题目：

题解：

class Solution {
public:int combinationSum4(vector<int>& nums, int target) {vector<int> dp(target + 1);dp[0] = 1;for (int i = 1; i <= target; i++) {for (int& num : nums) {if (num <= i && dp[i - num] < INT_MAX - dp[i]) {dp[i] += dp[i - num];}}}return dp[target];}
};