Submission #1157275

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Source Code Expand

#include <sstream>
#include <fstream>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <set>
#include <stack>
#include <map>
#include <string>
#include <queue>
#include <bitset>
using namespace std;

#define int long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define REP(i, a) for (int i = 0, _a = (a); i < _a; ++i)
#define REPD(i,n) for(int i = (n)-1; i >= 0; --i)

#define DEBUG(X) { cerr << #X << " = " << (X) << endl; }
#define PR(A, n) { cerr << #A << " = "; FOR(_, 1, n) cerr << A[_] << ' '; cerr << endl; }
#define PR0(A, n) { cerr << #A << " = "; REP(_, n) cerr << A[_] << ' '; cerr << endl; }

#define sqr(x) ((x) * (x))
#define ll long long
#define double long double
typedef pair<int, int> II;
#define PI (2 * acos((double)0))
#define __builtin_popcount __builtin_popcountll
#define SZ(x) ((int)(x).size())
#define ALL(a) (a).begin(), (a).end()
#define MS(a,x) memset(a, x, sizeof(a))
#define next ackjalscjaowjico
#define prev ajcsoua0wucckjsl
#define y1 alkscj9u20cjeijc
#define left lajcljascjljl
#define right aucouasocjolkjl
#define y0 u9cqu3jioajc

#define TWO(X) (1LL<<(X))
#define CONTAIN(S,X) ((S) & TWO(X))

double safe_sqrt(double x) { return sqrt(max((double)0.0, x)); }
int GI(int& x) { return scanf("%lld", &x); }

const int MN = 100111;

vector<int> ke[MN];
bool good;
int cnt;
int color[MN];

void dfs(int u) {
    ++cnt;
    for(int v : ke[u]) {
        if (color[v] < 0) {
            color[v] = 1 - color[u];
            dfs(v);
        }
        else {
            if (color[v] == color[u]) good = true;
        }
    }
}

int32_t main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout << (fixed) << setprecision(9);
    int n, m;
    while (cin >> n >> m) {
        FOR(i,1,n) ke[i].clear();
        FOR(i,1,m) {
            int u, v; cin >> u >> v;
            ke[u].push_back(v);
            ke[v].push_back(u);
        }

        memset(color, -1, sizeof color);

        int single = 0;
        int hasOddCycle = 0;
        int normal = 0;

        FOR(i,1,n) if (color[i] < 0) {
            cnt = 0;
            good = false;
            color[i] = 0;
            dfs(i);

            if (cnt == 1) single++;
            else if (good) hasOddCycle++;
            else normal++;
        }

        int res = 0;
        // single, x
        while (single > 0) {
            res += 2 * n - 1;
            --n;
            --single;
        }

        // normal, normal
        res += normal * (normal+1);

        // odd, odd
        res += hasOddCycle * (hasOddCycle + 1) / 2;

        // normal, odd
        res += normal * hasOddCycle * 2;

        cout << res << endl;
    }
    return 0;
}

Submission Info

Judge Result