蓝桥杯 审美课

 1 #include <bits/stdc++.h> 
 2 using namespace std;
 3 int A[50010]; //50000个学生 
 4 int ans[2000000];
 5 int sum;
 6 int main() {
 7     int n, m;
 8     cin >> n >> m; 
 9     for(int i = 0; i < n; i++) {
10         for(int j = 0; j < m; j++) {
11             int temp;
12             cin >> temp;
13             A[i] = (A[i] << 1) + temp;//2进制保存 
14         }
15         ans[A[i]]++;//获得每个答案的人数 
16         //cout << "A[i]:" << A[i] << " ans[A[i]]:" << ans[A[i]] << endl;
17     } 
18     int max = (1 << m) - 1;
19     for(int i = 0; i < n; i++) { 
20         int temp = A[i] ^ max;//按位取反 
21         //cout << "temp:" << temp << " ans[temp]:" << ans[temp] << endl;
22         sum += ans[temp] ;
23     }
24     cout << sum / 2 << endl;
25     return 0;
26 }