Submission #41750489

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Source Code Expand

#include <iostream>
#include <vector>

using namespace std;

int main() {
    int N, M;
    cin >> N >> M;

    vector<vector<int>> a(M, vector<int>(N));
    for (int i = 0; i < M; i++) {
        for (int j = 0; j < N; j++) {
            cin >> a[i][j];
        }
    }

    vector<vector<bool>> isEnemy(N + 1, vector<bool>(N + 1, false)); // 各人が不仲の可能性があるかを保持する配列 (1-indexed)
    int count = N*(N-1)/2; // 不仲の可能性がある二人組の数

    for (int i = 0; i < M; i++) {
        for (int j = 0; j < N - 1; j++) {
            int person1 = a[i][j];
            int person2 = a[i][j + 1];

            if (!isEnemy[person1][person2] && !isEnemy[person2][person1]) {
                isEnemy[person1][person2] = true;
                isEnemy[person2][person1] = true;
                count--;
            }
        }
    }

    cout << count << endl;

    return 0;
}

Submission Info

Judge Result