tj
2024-10-12 20:50:45
发布于:上海
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#include <iostream>
using namespace std;int n, sum, a[10000], s[10000]={0};long long all = 0;int main() {cin >> n >> sum;for (int i = 0; i < n; i++) cin >> a[i];for (int i = 0; i < n; i++) for (int j = 0; j < n; j++) s[a[i] + a[j]]++;for (int i = 0; i < n; i++) for (int j = 0; j < n; j++) if (sum - a[i] - a[j] > 0) all += s[sum - a[i] - a[j]];cout << all;return 0;}
这里空空如也
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