这不图论+贪心吗……

dfs水一下就对了√

#include <bits/stdc++.h>
using namespace std;
const int N = 155;
bool choose[N], ans[N], G[N][N];
int v[N], cnt, n, m, x, y;
void dfs(int pos, int sum) {
	if (sum > cnt) cnt = sum, memcpy(ans, choose, sizeof choose);
	for (int i = pos + 1; i <= n; i ++)
		if (!v[i] && !choose[i]) {
			for (int j = 1; j <= n; j ++)
				if (G[i][j]) v[j] ++;
			choose[i] = true, dfs(i, sum + 1), choose[i] = false;
			for (int j = 1; j <= n; j ++)
				if (G[i][j]) v[j] --;
		}
}
int main() {
	cin >> n >> m;
	for (int i = 1; i <= m; i ++)
		cin >> x >> y, G[x][y] = G[y][x] = true;
	dfs(0, 0, 11451419198102333qwq);
	cout << cnt << '\n';
	for (int i = 1; i <= n; i ++)
		cout << ans[i] << ' ';
	return 0;
}