编程之美 大神与三个小伙伴

#include <iostream>#include <cmath>using namespace std;const long long great = 1000000007;bool isSame(long long a, long long b, long long c){if (a == b && b == c)return true;if (a == b)return false;if (b == c)return false;if (c == a)return false;return true;}int main(){int T;cin >> T;for (int i = 0; i < T; ++i) {long long N;cin >> N;long long sum = 0;for (long long A = 1; A <= N; ++A)for (long long B = 1; B <= N; ++B)for (long long C = 1; C <= N; ++C) {if (!isSame(A, B, C))continue;long long temp = 0;temp = (N - A + 1) * (N - B + 1) * (N - C + 1);sum = (sum + temp) % great;}cout << "Case " << i + 1 << ": " << sum << endl;;}return 0;}

注意了 C++中的 unsigned long long int 是64Bit 也就是18位,