提出 #69547367

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ソースコード 拡げる

// To scale the heights, one must embrace the fall.
#include <bits/stdc++.h>
#define fi first
#define se second
#define int long long
#define pb emplace_back
#define F(i, a, b) for (int i = (a); i <= (b); ++i)
#define dF(i, a, b) for (int i = (a); i >= (b); --i)
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

const int N = 200005, M = (N << 1), inf = 1e16, mod = 1e9 + 7;
int n, m, c, a[N];
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    cin >> n >> m;
    F(i, 1, m) {
        int u, v;
        cin >> u >> v;
        a[u]++, a[v]++;
    } 
    F(i, 1, n) if (a[i] % 2 != (n - 1) % 2) c++;
    cout << n * (n - 1) / 2 - c / 2 << '\n';
    return 0;
}

提出情報

ジャッジ結果