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：
1 #include<iostream> 2 #include<cstdlib> 3 #include<cstdio> 4 #include<cstring> 5 #define maxn 110 6 using namespace std; 7 int parent[maxn*maxn]; 8 char map[maxn][maxn]; 9 int find(int x) 10 { 11 int s; 12 for(s=x;parent[s]>=0;s=parent[s]); 13 while(s!=x) 14 { 15 int tmp=parent[x]; 16 parent[x]=s; 17 x=tmp; 18 } 19 return s; 20 } 21 void Union(int r1,int r2) 22 { 23 int R1=find(r1); 24 int R2=find(r2); 25 int tmp=parent[R1]+parent[R2]; 26 if(parent[R1]>parent[R2]) 27 { 28 parent[R1]=R2; 29 parent[R2]=tmp; 30 } 31 else 32 { 33 parent[R2]=R1; 34 parent[R1]=tmp; 35 } 36 } 37 int main() 38 { 39 int m,n; 40 while(scanf("%d%d",&m,&n)!=EOF) 41 { 42 if(m<0 || n<0) break; 43 for(int i=0;i<m;i++) 44 scanf("%s",map[i]); 45 for(int i=0;i<m*n;i++) 46 parent[i]=-1; 47 for(int i=0;i<m;i++) 48 for(int j=0;j<n;j++) 49 { 50 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')) 51 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') 52 Union(i*n+j,(i-1)*n+j); 53 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')) 54 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') 55 Union(i*n+j,i*n+j-1); 56 57 } 58 int ans=0; 59 for(int i=0;i<m*n;i++) 60 if(parent[i]<0) ans++; 61 cout<<ans<<endl; 62 } 63 return 0; 64 }
