C++98 代码：统计方格图中好朋友的数量

#include #include #include

using namespace std;

int main() { int n, m; cin >> n >> m;

vector<vector<int>> grid(n, vector<int>(m));
for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
        cin >> grid[i][j];
    }
}

map<int, int> count;
for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
        count[grid[i][j]]++;
    }
}

int sum = 0;
for (map<int, int>::iterator it = count.begin(); it != count.end(); it++) {
    sum += it->second * (it->second - 1);
}

cout << sum << endl;

return 0;

}