P8605 [蓝桥杯 2013 国 AC] 网络寻路
题目
代码
cpp
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <math.h>
#include <queue>
#include <cctype>
using namespace std;
int main() {
int n, m;
long long r = 0;
cin >> n >> m;
vector<int> d(n + 1, 0);
vector<int> a(n, 0);
vector<int> b(n, 0);
for (int i = 0; i < m; i++) {
cin >> a[i] >> b[i];
d[a[i]]++;
d[b[i]]++;
}
for (int i = 0; i < m; i++) {
if (d[a[i]] > 1 && d[b[i]] > 1) {
r += ((d[a[i]] - 1 ) * (d[b[i]] - 1)) * 2;
}
}
cout << r << endl;
return 0;
}