hdu1198 Farm Irrigation 并查集

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1198

简单并查集

分别合并竖直方向和水平方向即可

代码：

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#define maxn 110
using namespace std;
int parent[maxn*maxn];
char map[maxn][maxn];
int find(int x)
{
   int s;
   for(s=x;parent[s]>=0;s=parent[s]);
   while(s!=x)
   {
      int tmp=parent[x];
      parent[x]=s;
      x=tmp;
   }
   return s;
}
void Union(int r1,int r2)
{
     int R1=find(r1);
     int R2=find(r2);
     int tmp=parent[R1]+parent[R2];
     if(parent[R1]>parent[R2])
     {
          parent[R1]=R2;
          parent[R2]=tmp;
     }
     else
     {
         parent[R2]=R1;
         parent[R1]=tmp;
     }
}
int main()
{
    int  m,n;
    while(scanf("%d%d",&m,&n)!=EOF)
    {
        if(m<0 || n<0) break;
        for(int i=0;i<m;i++)
         scanf("%s",map[i]);
        for(int i=0;i<m*n;i++)
        parent[i]=-1;
        for(int i=0;i<m;i++)
         for(int j=0;j<n;j++)
         {
            if(i>0 && (map[i][j]=='A' ||map[i][j]=='B'||map[i][j]=='E'||map[i][j]=='G'||map[i][j]=='H'||map[i][j]=='J'||map[i][j]=='K'))
            if(map[i-1][j]=='C'||map[i-1][j]=='D'||map[i-1][j]=='E'||map[i-1][j]=='H'||map[i-1][j]=='I'||map[i-1][j]=='J'||map[i-1][j]=='K')
            Union(i*n+j,(i-1)*n+j);
            if(j>0&&(map[i][j]=='A'||map[i][j]=='C'||map[i][j]=='F'||map[i][j]=='G'||map[i][j]=='H'||map[i][j]=='I'||map[i][j]=='K'))
            if(map[i][j-1]=='B'||map[i][j-1]=='D'||map[i][j-1]=='F'||map[i][j-1]=='G'||map[i][j-1]=='I'||map[i][j-1]=='J'||map[i][j-1]=='K')
            Union(i*n+j,i*n+j-1);
         
        }
        int ans=0;
        for(int i=0;i<m*n;i++)
        if(parent[i]<0) ans++;
        cout<<ans<<endl;
    }
return 0;
}