Submission #2894517

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Source Code Expand

#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll MOD = (1e+9)+7;
const ll INF = (ll)1000000007 * 1000000007;
const double EPS = 1e-9;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
typedef complex<ld> Point;
const ld eps = 1e-11;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
typedef pair<ld, ld> LDP;
bitset<701> exi;
vector<int> G[700],cG[700];
int main() {
	int n, m; cin >> n >> m;
	int a, b;
	rep(i, m) {
		cin >> a >> b; a--; b--;
		G[a].push_back(b); G[b].push_back(a);
	}
	rep(i, n) {
		int used[700] = {};
		int len = G[i].size();
		rep(j, len) {
			used[G[i][j]] = 1;
		}
		rep(j, n) {
			if (i == j)continue;
			if (!used[j]) {
				cG[i].push_back(j);
			}
		}
	}
	int used[700] = {};
	bool g = true;
	queue<P> que;
	rep(i, n) {
		if (used[i])continue;
		used[i] = 1;
		bool chk = true;
		queue<int> q; q.push(i);
		int cnt1 = 0; int cnt2 = 0;
		while (!q.empty()) {
			int len = q.size();
			if (chk)cnt1 += len;
			else cnt2 += len;
			rep(j, len) {
				int nex = q.front(); q.pop();
				int len2 = cG[nex].size();
				rep(k, len2) {
					int v = cG[nex][k];
					if (used[v]) {
						if ((chk&&used[v] == 1) || ((!chk) && used[v] == -1))g = false;
						continue;
					}
					if (chk)used[v] = -1;
					else used[v] = 1;
					q.push(v);
				}
			}
			chk = !chk;
		}
		que.push({ cnt1,cnt2 });
	}
	if (!g) {
		cout << -1 << endl;
	}
	else {
		exi[0] = 1;
		int len = que.size();
		rep(i, len) {
			P nex = que.front(); que.pop();
			int x = nex.first; int y = nex.second;
			exi = (exi << x) | (exi << y);
		}
		int mi = (int)MOD;
		rep(i, n + 1) {
			if (exi[i]) {
				int csum1 = i * (i - 1) / 2;
				int csum2 = (n - i)*(n - i - 1) / 2;
				mi = min(mi, csum1 + csum2);
			}
		}
		cout << mi << endl;
	}
	return 0;
}

Submission Info

Judge Result