简单的并查集
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1 /* 2 并查集 3 */ 4 #include<stdio.h> 5 #include<string.h> 6 #include<stdlib.h> 7 #include<algorithm> 8 #include<iostream> 9 #include<queue> 10 //#include<map> 11 #include<math.h> 12 using namespace std; 13 typedef long long ll; 14 //typedef __int64 int64; 15 const int maxn = 1005; 16 const int inf = 0x7fffffff; 17 const double pi=acos(-1.0); 18 const double eps = 1e-8; 19 int fa[ maxn ]; 20 void init( int n ){ 21 for( int i=1;i<=n;i++ ) 22 fa[ i ]=i; 23 } 24 int find( int x ){ 25 if( fa[x]==x ) return x; 26 fa[x]=find( fa[x] ); 27 return fa[x]; 28 } 29 void union_xy( int x,int y ){ 30 int fa_x,fa_y; 31 fa_x = find( x ); 32 fa_y = find( y ); 33 if( fa_x>fa_y ) 34 fa[ fa_y ]=fa_x; 35 else 36 fa[ fa_x ]=fa_y; 37 } 38 int main(){ 39 int ca; 40 scanf("%d",&ca); 41 while( ca-- ){ 42 int n,m; 43 scanf("%d%d",&n,&m); 44 init( n ); 45 int a,b; 46 while( m-- ){ 47 scanf("%d%d",&a,&b); 48 union_xy( a,b ); 49 } 50 int cnt=0; 51 for( int i=1;i<=n;i++ ){ 52 if( fa[i]==i ) 53 cnt++; 54 } 55 printf("%d\n",cnt); 56 } 57 return 0; 58 }