1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45

#include <iostream>
#include <vector>

const int M = 1'000'000'007;

class Solution {
public:
    int countPartitions(std::vector<int>& nums, int k) {
        long long sum = 0;
        for (int num : nums) {
            sum += num;
        }
        if (sum < 2 * k) {
            return 0;
        }
        
        int dp[1001] = { 0 };
        int res = 1;
        dp[0] = 2;
        
        for (int num : nums) {
            res *= 2;
            if (res >= M) {
                res -= M;
            }
            for (int i = k - 1; i >= num; --i) {
                if (dp[i - num]) {
                    dp[i] += dp[i - num];
                    if (dp[i] >= M) {
                        dp[i] -= M;
                    }
                }
            }
        }
        
        for (int i : dp) {
            res -= i;
            if (res < 0) {
                res += M;
            }
        }
        
        return res;
    }
};