关押罪犯

 1     sort(edge + 1, edge + m + 1, cmp);
 2     for(int i = 1; i <= (n << 1); i++) fa[i] = i;
 3     int xx, yy;
 4     for(int i = 1; i <= m; i++){
 5         xx = edge[i].x, yy = edge[i].y;
 6         if(find(xx) == find(yy)){
 7             printf("%d", edge[i].w);
 8             return 0;
 9         }
10         else {
11             fa[find(xx)] = fa[find(yy + n)];//!!!
12             fa[find(yy)] = fa[find(xx + n)];
13         }
14     }
15     printf("0");