HDU 1198——Farm Irrigation

並查集 

 先用一個數組a來儲存A-K方塊上下左右是否有河道。

然後使用並查集，最後判斷有多少個不同的集合。

#include<cstdio>#include<iostream>#include<cstring>using namespace std;#define N 55#define M 55int a[11][4]={  1,0,0,1, 1,1,0,0,0,0,1,1,0,1,1,0,1,0,1,0,0,1,0,1,1,1,0,1,1,0,1,1,0,1,1,1,1,1,1,0,1,1,1,1 };char map[N][M];int father[N*M];int num[N*M];int GetFather(int x){while(father[x]!=-1){x=father[x];}return x;}void Union(int x,int y){int fx=GetFather(x);int fy=GetFather(y);if(fx!=fy)father[fx]=fy;}int main(){int n,m;while(~scanf("%d%d",&n,&m)&&n+m>=0){memset(father,-1,sizeof(father));for(int i=0;i<n;i++)cin>>map[i];for(int i=0;i<n;i++)for(int j=0;j<m;j++){if(i>=1&&a[map[i][j]-'A'][0]&&a[map[i-1][j]-'A'][2])//shangUnion(m*i+j,m*(i-1)+j);if(i<n-1&&a[map[i][j]-'A'][2]&&a[map[i+1][j]-'A'][0])//xiaUnion(m*i+j,m*(i+1)+j);if(j>=1&&a[map[i][j]-'A'][3]&&a[map[i][j-1]-'A'][1])//zuoUnion(m*i+j,m*i+j-1);if(j<m-1&&a[map[i][j]-'A'][1]&&a[map[i][j+1]-'A'][3])//youUnion(m*i+j,m*i+j+1);}memset(num,0,sizeof(num));for(int i=0;i<n*m;i++){if(father[i]==-1)num[i]=1;}int ans=0;for(int i=0;i<n*m;i++)if(num[i])ans++;printf("%d\n",ans);}return 0;}