Densest subgraph

input/code.cpp: In function 'int find_min()':
input/code.cpp:72:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (g[i].size() < mcnt) {
       ~~~~~~~~~~~~^~~~~~
input/code.cpp:83:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (g[i].size() == mcnt) {
       ~~~~~~~~~~~~^~~~~~~

#include <iostream>
#include <vector>
#include <set>

using namespace std;
typedef long double ld;
#define F first
#define S second

int n, m;
set<int> g[105];
bool rm[105];

int cmp[105];
int cmpv[105];
int cmpe[105];

ld mxrt = 0.0;
int resn = 0;
int resm = 0;
vector<int> resnd;

pair<int, int> density() {
	int vc = 0;
	int ec = 0;
	for (int i = 1; i <= n; ++i) {
		if (rm[i]) continue;
		vc++;
		ec += g[i].size();
	}
	ec /= 2;
	return {vc, ec};
}

void dfs(int s, int cc) {
	if (cmp[s] != 0) return;
	cmp[s] = cc;
	cmpv[cc]++;
	cmpe[cc] += g[s].size();

	for (int a : g[s]) {
		dfs(a, cc);
	}
}

void ccmpd() {
	for (int i = 1; i <= n; ++i) {
		cmp[i] = 0;
		cmpe[i] = 0;
		cmpv[i] = 0;
	}
	int ccmp = 0;
	for (int i = 1; i <= n; ++i) {
		if (rm[i]) continue;
		if (cmp[i] == 0) {
			ccmp++;
			dfs(i, ccmp);
		}
	}

	for (int i = 1; i <= n; ++i) {
		cmpe[i] /= 2;
	}
}

int find_min() {
	int mcnt = 1000000000;
	int mind = -1;
	ld bres = 1000000000.0;
	for (int i = 1; i <= n; ++i) {
		if (rm[i]) continue;
		if (g[i].size() < mcnt) {
			mcnt = g[i].size();
			mind = i;
			int necnt = cmpe[cmp[i]]; // -g[i].size();
			int nvcnt = cmpv[cmp[i]]; // -1;
			ld cres = 0.0;
			if (nvcnt > 0) {
				cres = necnt / ((ld)nvcnt);
			}
			bres = cres;
		}
		if (g[i].size() == mcnt) {
			int necnt = cmpe[cmp[i]]; // -g[i].size();
			int nvcnt = cmpv[cmp[i]]; // -1;
			ld cres = 0.0;
			if (nvcnt > 0) {
				cres = necnt / ((ld)nvcnt);
			}
			if (cres <= bres) {
				bres = cres;
				mcnt = g[i].size();
				mind = i;
			}
		}
	}
	return mind;
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cin >> n >> m;
	for (int i = 0; i < m; ++i) {
		int a, b;
		cin >> a >> b;
		g[a].insert(b);
		g[b].insert(a);
	}
	int gsz = n;
	while (gsz > 0) {
		auto cden = density();
		ld crt = cden.S / ((ld)cden.F);
		if (crt > mxrt) {
			mxrt = crt;
			resn = cden.F;
			resm = cden.S;
			resnd.clear();
			for (int i = 1; i <= n; ++i) {
				if (rm[i]) continue;
				resnd.push_back(i);
			}
		}

		ccmpd();

		int cmin = find_min();
		//cout << "remove " << cmin << endl;
		rm[cmin] = true;
		for (int a : g[cmin]) {
			g[a].erase(cmin);
		}
		gsz--;
	}
	cout << resn << " " << resm << "\n";
	for (int a : resnd) {
		cout << a << " ";
	}
	cout << "\n";
	return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED