hdu 1829 A Bug's Life

两种代码

1：

/*
以往的并查集题目是读入的是相同的，这和题目读入的是不同的
用set[]数组来判断
*/

#include"stdio.h"
#include"string.h"
int set[2010],v[2010];

int find(int x)
{
	int r=x;
	while(r!=set[r])
		r=set[r];
	return r;
}
void join(int x,int y)
{
	int a,b;
	a=find(x);b=find(y);
	if(a<b) set[b]=a;
	else set[a]=b;
}
int main()
{
	int i,n,m,t,flag,cas,a,b;
	scanf("%d",&t);
	cas=1;
	while(t--)
	{
		scanf("%d%d",&n,&m);
		memset(v,0,sizeof(v));
		flag=0;
		for(i=1;i<=n;i++)
			set[i]=i;
		for(i=0;i<m;i++)
		{
			scanf("%d%d",&a,&b);
			if(flag)continue;
			if(find(a)==find(b))
			{
				flag=1;continue;
			}
			else
			{
				if(v[a]==0) v[a]=b;//v[a]表示与a性别相反
				else join(v[a],b);
				if(v[b]==0) v[b]=a;
				else join(v[b],a);
			}
		}
		printf("Scenario #%d:\n",cas++);
		if(flag)
			printf("Suspicious bugs found!\n");
		else
			printf("No suspicious bugs found!\n");
		printf("\n");
	}
	return 0;
}

:2：

#include <iostream>
using namespace std;

int n,r;
//don't use set and sex next time. it is easy to confuse them.
int set[2002];//store the root 
bool sex[2002];//store the relationship with the root. 1 means different sex, 0 mean same sex.

int find(int x)//find the root of x
{
    if(set[x]==x)return x;//root is self
    int t;
    t=set[x];
    set[x]=find(set[x]);//find the real root
    sex[x]=(sex[x]+sex[t])%2;//compare the sex with root 
    //sex[x]is the relation between x and it's former root. sex[t] is the relation between the former root with the real root
    //plus and remaind can get the relation between x and the real root
    return set[x];
}

void merge(int x,int y)
{
     int fx,fy;
     fx=find(x);
     fy=find(y);
     set[fx]=fy;//put x into y
     sex[fx]=(sex[x]+sex[y]+1)%2;
     //x compare to its root, y compare to its root. 1 means x and y are different sex.
     //plus and remaind so we get fx compare to fy
}
    

int main()
{
    int cas;
    cin>>cas;
    int ci=0;
    int x,y;//temp
    while(cas--)
    {
        ci++;
        int i;
        int flag=0;//0 means no suspicious
        scanf("%d%d",&n,&r);//number of bug, relation
        for(i=0;i<n;i++)//it is n,not r...
        {
            set[i]=i;//everybug's root is it self
            sex[i]=0;
        }
            
        
        while(r--)//it is r,not n...
        {
            
            scanf("%d%d",&x,&y);
            if(find(x)==find(y))
            //have the same root, which means they can be compared
            {
                if(sex[x]==sex[y])//sex is the same
                flag=1;
            }
            else
            merge(x,y);//merge them into one root
            // because the data is simple, so we just simply put x into y. no need to worry about the height of x and y
        }
        printf("Scenario #%d:\n",ci);
            if(flag)
                printf("Suspicious bugs found!\n");
            else
                printf("No suspicious bugs found!\n");
        printf("\n");
    }
    system("pause");
    return 0;
}