代码

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e4 + 5;
template <typename T> void read(T &x) {
	x = 0; int f = 1;
	char ch = getchar();
	for (; !isdigit(ch); ch = getchar()) if (ch == '-') f = -f;
	for (; isdigit(ch); ch = getchar()) x = x * 10 + ch - '0';
	x *= f;
}
struct edge {int dest, nxt, num; };
int n, m, head[MAXN], ans[MAXN];
int tot, dis, cnt, now[MAXN]; edge a[MAXN * 2];
vector <int> circle;
vector <pair <int, int> > b[MAXN];
int ftype[MAXN], father[MAXN], depth[MAXN];
void work(int pos, int fa) {
	now[++cnt] = pos;
	for (int i = head[pos]; i != 0; i = a[i].nxt)
		if (a[i].num != dis && a[i].dest != fa) work(a[i].dest, pos);
}
void checkans(int x) {
	dis = x, cnt = 0;
	work(1, 0);
	bool flg = false;
	for (int i = 1; i <= n; i++)
		if (now[i] < ans[i]) {
			flg = true;
			break;
		} else if (now[i] > ans[i]) break;
	if (flg) {
		for (int i = 1; i <= n; i++)
			ans[i] = now[i];
	}
}
void dfs(int pos, int fa, int type) {
	if (circle.size() != 0) return;
	depth[pos] = depth[fa] + 1;
	ftype[pos] = type;
	father[pos] = fa;
	for (int i = head[pos]; i != 0 && circle.size() == 0; i = a[i].nxt)
		if (a[i].dest != fa) {
			if (depth[a[i].dest]) {
				circle.push_back(a[i].num);
				int tmp = pos;
				while (tmp != a[i].dest) {
					circle.push_back(ftype[tmp]);
					tmp = father[tmp];
				}
				return;
			}
			dfs(a[i].dest, pos, a[i].num);
		}
}
bool cmp(pair <int, int> x, pair <int, int> y) {
	if (x.first == y.first) return x.second < y.second;
	else return x.first > y.first;
}
int main() {
	read(n), read(m);
	for (int i = 1; i <= m; i++) {
		int x, y; read(x), read(y);
		b[x].push_back(make_pair(y, i));
		b[y].push_back(make_pair(x, i));
	}
	for (int i = 1; i <= n; i++) {
		sort(b[i].begin(), b[i].end(), cmp);
		for (unsigned j = 0; j < b[i].size(); j++)
			a[++tot] = (edge) {b[i][j].first, head[i], b[i][j].second}, head[i] = tot;
	}
	ans[1] = n + 1;
	if (m == n) {
		dfs(1, 0, 0);
		for (unsigned i = 0; i < circle.size(); i++)
			checkans(circle[i]);
	} else checkans(0);
	for (int i = 1; i <= n; i++)
		printf("%d ", ans[i]);
	printf("\n");
	return 0;
}

评测结果