hdu1272-小希的迷宫

题目链接 http://vjudge.net/problem/HDU-1272

 

解题思路

需要判断图是否连通 且 只有一个连通分量

注意只有0 0的情况。

 

代码

#include<stdio.h>
#include<string.h>
#define SET_SIZE 100010
int s[SET_SIZE];
bool vis[SET_SIZE];
void MakeSet(int n)
{
	for(int i=1; i<=n; i++) s[i] = i;
}
int FindFather(int x)
{
	if(s[x] != x)
		s[x] = FindFather(s[x]);
	return x;
}
void UnionSet(int fx, int fy)
{
	s[fx] = fy;
}
int main()
{
	int x, y;
	scanf("%d%d", &x, &y);
	while(!(x == -1 && y == -1)) {
		bool flag = false;
		int count = 0;
		int vNum = 0, edgeNum = 0;
		MakeSet(SET_SIZE);
		memset(vis, 0, sizeof(vis));
		while(!(x == 0 && y == 0)) {
			count++;
			if(!vis[x]) { vNum++; vis[x] = true; }
			if(!vis[y]) { vNum++; vis[y] = true; }
			if(!flag) {
				int fx = FindFather(x);
				int fy = FindFather(y);
				if(fx == fy) flag = true;
				else {
					UnionSet(fx, fy);
					edgeNum++;
				}
			}
			scanf("%d%d", &x, &y);
		}
		if(count == 0) printf("Yes\n");
		else{
			if(!flag && vNum == edgeNum + 1) printf("Yes\n"); 
			else printf("No\n");
		}
		scanf("%d%d", &x, &y);
	}
	return 0;
}