LA 5135 Mining Your Own Business

仅作代码分享

#include<cstdio>
#include<cmath>
#include<cstring>
#include<vector>
#include<algorithm>
#include<stack>
#include<queue>
using namespace std;
typedef long long ll;

const int MAXN = 50007;
struct edge {
	int u, v;
	edge(int tu, int tv):u(tu), v(tv) {}
};
vector<int> G[MAXN], bcc[MAXN];
int pt[MAXN], low[MAXN];
int bccno[MAXN];
int bccn, dt;
bool iscut[MAXN];

stack<edge> sg;

int dfs(int u, int fa) {
	pt[u] = low[u] = ++dt;
	int i, sz = G[u].size(), child = 0;
	for(i = 0; i < sz; i++) {
		int v = G[u][i];
		edge tmp(u,v);
		if( !pt[v] ) {
			child ++;
			sg.push(tmp);
			low[u] = min(low[u], dfs(v, u));
			if(low[v] >= pt[u]) {
				iscut[u] = true;
				bccn ++; bcc[bccn].clear();
				while( !sg.empty() ) {
					tmp = sg.top(); sg.pop();
					if(bccno[tmp.u] != bccn) {
						bccno[tmp.u] = bccn;
						bcc[bccn].push_back(tmp.u);
					}
					if(bccno[tmp.v] != bccn) {
						bccno[tmp.v] = bccn;
						bcc[bccn].push_back(tmp.v);
					}
					if(tmp.u == u && tmp.v == v) break;
				}
			}
		}
		else if(pt[v] < pt[u] && v != fa) {
			sg.push(tmp);
			low[u] = min(low[u], pt[v]);
		}
	}
	if(fa < 1 && child < 2) iscut[u] = false;
	return low[u];
}
void getbcc(int n) {
	while( !sg.empty() ) sg.pop();
	bccn = dt = 0;
	memset(pt, 0, sizeof(pt));
	memset(bccno, 0, sizeof(bccno));
	memset(iscut, 0, sizeof(iscut));
	for(int i = 1; i <= n; i++)
		if( !pt[i] ) dfs(i, 0);
}

int main() {
	int n, id = 0;
	while(~scanf("%d", &n), n) {
		int i, j, u, v, N = 1;
		for(i = 1; i <= n+1; i++) G[i].clear();
		for(i = 1; i <= n; i++) {
			scanf("%d%d", &u, &v);
			N = max(N, u);
			N = max(N, v);
			G[u].push_back(v);
			G[v].push_back(u);
		}

		getbcc(N);
		ll ans0 = 0, ans1 = 1;
		if(bccn < 2) {
			ans0 = 2;
			ans1 = (ll)N * (N - 1) / 2;
		}
		else {
			for(i = 1; i <= bccn; i++) {
				int ncut = 0, sz = bcc[i].size();
				for(j = 0; j < sz; j++)
					if(iscut[bcc[i][j]]) ncut++;
				if(ncut > 1) continue;
				ans0 ++;
				ans1 *= sz - 1;
			}
		}
		printf("Case %d: %lld %lld\n", ++id, ans0, ans1);
	}
	return 0;
}