并查集合并

#include<iostream> using namespace std; const int MAX = 10010; int father[MAX],root[MAX]; int findfather(int x){if(x==father[x]) return x;else{int F=findfather(father[x]);father[x]=F;return F;} } void Union(int a , int b){int faA=findfather(a);int fbB=findfather(b);if(faA!=fbB){father[faA]=fbB;} } void init(){for(int i=0;i<MAX;i++){father[i]=i;root[i]=0;} } int n,q; int main(){init();cin>>n;int maxbirds=0; for(int i=0;i<n;i++){int nbirds,firstbird;scanf("%d%d",&nbirds,&firstbird);if(firstbird>maxbirds) maxbirds=firstbird;for(int j=1;j<nbirds;j++){int bird;scanf("%d",&bird);if(bird>maxbirds) maxbirds=bird;Union(firstbird,bird);}}int trees=0;for(int i=1;i<=maxbirds;i++){int fa=findfather(i);root[fa]++;if(root[fa]==1) trees++;}printf("%d %d\n",trees,maxbirds);cin>>q;while(q--){int a , b;scanf("%d%d",&a,&b);if(findfather(a)==findfather(b)) printf("Yes\n");else printf("No\n");} }

非遞歸壓縮并查集

int father[MAX]; bool isRoot[MAX];//判根 int findFather( int x ) { int a = x; while( x != father[x] ) { x = father[x]; } while( a != father[a] ) { int z = a; a = father[a]; father[z] = x; } return x; } void Union( int a, int b ) { int faA = findFather( a ); int faB = findFather( b ); if( faA != faB ) { father[faA] = faB; } } void init( int n ) { for( int i = 1; i <= n; i++ ) { //從1開(kāi)始father[i] = i; isRoot[i] = false; } }

轉(zhuǎn)載于:https://www.cnblogs.com/demian/p/6102945.html

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