POJ P2492 A Bug's Life 并查集

2
3 3
1 2
2 3
1 3
4 2
1 2
3 4

Scenario #1:
Suspicious bugs found!

Scenario #2:
No suspicious bugs found!

#include <cstdio>

int set[5010],offset[5010];
int n,m,k,i,j,x,y;
bool flag;

int FindSet(int x);
void Union(int x, int y);
int main()
{
scanf("%d",&k);
for (int i = 1; i <= k; ++i){
scanf("%d%d", &n, &m);
flag = true;
for (j=1;j<=n;++j){
set[j] = j;
offset[j] = 0;
}
for (j = 1; j <= m; ++j){
scanf("%d%d", &x, &y);
if (flag)
if (FindSet(x) != FindSet(y))
Union(x, y);
else
if (offset[x] == offset[y]) flag=0;
}
if (flag)
printf("Scenario #%d:\nNo suspicious bugs found!\n", i);
else
printf("Scenario #%d:\nSuspicious bugs found!\n", i);
if (i != k) printf("\n");
}
return 0;
}

int FindSet(int x){
if (x != set[x]){
int temp=set[x];
set[x] = FindSet(set[x]);
offset[x]^=offset[temp];
}
return set[x];
}

void Union(int x, int y){
int fx = FindSet(x);
int fy = FindSet(y);
set[fy] = fx;
offset[fy] = offset[x]^offset[y]^1;
return;
}