HDU - 4786 Fibonacci Tree

#include<bits/stdc++.h>
using namespace std;
int T,i,j,n,fa[200000],x[200000],y[200000],m,fib[200000];
pair<int,int> a[200000];
int ask(int x){if(fa[x]==x)return x;else return fa[x]=ask(fa[x]);}
int main()
{
    scanf("%d",&T);
    fib[1]=1,fib[2]=2;
    for (i=3;i<=1000;i++)fib[i]=fib[i-1]+fib[i-2];
    int t;
    for (t=1;t<=T;t++)
    {
        printf("Case #%d: ",t);
        scanf("%d%d",&n,&m);
        for (i=1;i<=n;i++)fa[i]=i;
        for (i=1;i<=m;i++)
            scanf("%d%d%d",&x[i],&y[i],&a[i].first),a[i].second=i;
        sort(a+1,a+1+m);
        int tot=0,totw1=0;
        for (i=1;i<=m;i++)
        {
            int fx=ask(x[a[i].second]),fy=ask(y[a[i].second]);
            if(fx!=fy)
            {
                tot++;
                if(a[i].first)totw1++;
                fa[fx]=fy;
            }
        }
        if(tot!=n-1)
        {
            puts("No");
            continue;
        }
        for (i=1;i<=n;i++)fa[i]=i;
        int totw2=0;
        for (i=m;i>=1;i--)
        {
            int fx=ask(x[a[i].second]),fy=ask(y[a[i].second]);
            if(fx!=fy)
            {
                if(a[i].first)totw2++;
                fa[fx]=fy;
            }
        }
        bool answer=false;
        for (i=1;i<=1000;i++)if(totw1<=fib[i]&&fib[i]<=totw2)
        {
            answer=true;
            break;
        }
        if(answer)puts("Yes");else puts("No");
    }
    return 0;
}