【HDOJ】3560 Graph’s Cycle Component

并查集的路径压缩。

 #include <stdio.h>
 #include <string.h>

 #define MAXNUM 100005

 int deg[MAXNUM], bin[MAXNUM];
 char isCycle[MAXNUM];

 int find(int x) {
     int r = x;
     int i = x, j;

     while (r != bin[r])
         r = bin[r];

     while (i != r) {
         j = bin[i];
         bin[i] = r;
         i = j;
     }

     return r;
 }

 void merge(int x, int y) {
     int fx;
     int fy;

     fx = find(x);
     fy = find(y);
     if (fx != fy)
         bin[fx] = fy;
 }

 int main() {
     int n, m;
     int i, x, y;

     while (scanf("%d %d", &n, &m)!=EOF && (n||m)) {
         for (i=; i<n; ++i)
             bin[i] = i;
         memset(isCycle, , sizeof(isCycle));
         memset(deg, , sizeof(deg));
         while (m--) {
             scanf("%d %d", &x, &y);
             deg[x]++;
             deg[y]++;
             merge(x, y);
         }
         m = ;
         for (i=; i<n; ++i) {
             x = find(i);
             if (isCycle[x] == ) {
                 ++m;
                 isCycle[x] = ;
             }
         }
         for (i=; i<n; ++i)
             if (deg[i] != )
                 isCycle[bin[i]] = ;
         x = ;
         for (i=; i<n; ++i)
             if (isCycle[i])
                 ++x;
         printf("%d %d\n", m, x);
     }

     return ;
 }