跟 食物链 完全一样
并查集即可。。
1 #include <cstdio> 2 #include <cstring> 3 using namespace std; 4 #define N 100100 5 6 int rank[3*N+100]; 7 int par[3*N+100]; 8 int n,m; 9 10 void init(int n) { 11 for (int i=1;i<=n;i++) { 12 rank[i]=0; 13 par[i]=i; 14 } 15 } 16 17 int find(int x) { 18 if (par[x]==x) return x; 19 return par[x]=find(par[x]); 20 } 21 22 void unite(int x,int y) { 23 x=find(x); y=find(y); 24 if (x==y) return; 25 if (rank[x]<rank[y]) par[x]=y; 26 else { 27 par[y]=x; 28 if (rank[x]==rank[y]) x++; 29 } 30 } 31 32 bool same(int x,int y) { 33 return find(x)==find(y); 34 } 35 36 int main() { 37 scanf("%d%d",&n,&m); 38 int ans=0; 39 init(3*N+10); 40 for (int i=0;i<m;i++) { 41 int k,x,y; 42 scanf("%d%d%d",&k,&x,&y); 43 if (x>N || x<1 || y>N || y<1) continue; 44 if (k==1) { 45 if (x==y) { 46 ans++; 47 continue; 48 } 49 if (same(x,y+N) || same(x,y+2*N)) 50 continue; 51 else { 52 unite(x,y); 53 unite(x+N,y+N); 54 unite(x+2*N,y+2*N); 55 ans++; 56 } 57 } 58 else { 59 if (x==y) continue; 60 if (same(x,y) || same(x,y+2*N)) 61 continue; 62 else { 63 unite(x,y+N); 64 unite(x+N,y+2*N); 65 unite(x+2*N,y); 66 ans++; 67 } 68 } 69 } 70 printf("%d",ans); 71 }