CODECHEF: Funny gnomes ( Sparse Table , BitSet )

CODECHEF: Funny gnomes ( Sparse Table + Kth LCA LOGIC )

///==================================================///
///                HELLO WORLD !!                    ///
///                  IT'S ME                         ///
///               BISHAL GAUTAM                      ///
///         [ bsal.gautam16@gmail.com ]              ///
///==================================================///
#include<bits/stdc++.h>
#define X first
#define Y second
#define mpp make_pair
#define nl printf("\n")
#define SZ(x) (int)(x.size())
#define pb(x) push_back(x)
#define pii pair<int,int>
#define pll pair<ll,ll>
///---------------------
#define S(a) scanf("%d",&a)
#define P(a) printf("%d",a)
#define SL(a) scanf("%lld",&a)
#define S2(a,b) scanf("%d%d",&a,&b)
#define SL2(a,b) scanf("%lld%lld",&a,&b)
///------------------------------------
#define all(v) v.begin(),v.end()
#define CLR(a) memset(a,0,sizeof(a))
#define SET(a) memset(a,-1,sizeof(a))
#define fr(i,a,n) for(int i=a;i<=n;i++)
using namespace std;
typedef long long ll;

///  Digit     0123456789012345678 ///
#define MX     502
#define inf    2000000010
#define MD     1000000007
#define eps    1e-9
///===============================///

const int LN=30;
int n,m;
bitset<501>dp[MX][LN];
int main() {
    int tc,cs=1,i,j,k,x;
    S(n);
    for(int i=1; i<=n; i++) {
        for(int j=1; j<=n; j++) {
            S(x);
            if(x)dp[i][0].set(j);
        }
    }
    for(int j=1; j<LN; j++) {
        for(int i=1; i<=n; i++) {
            for(int k=1; k<=n; k++) {
                if( dp[i][j-1].test(k) ) {
                    dp[ i ][ j ]|=dp[ k ][ j-1 ];
                }
            }
        }
    }
    S(m);
    while(m--) {
        S2(k,x);
        bitset<501>b;
        b.set(x);
        for(int i=0; i<LN; i++) {
            if(k&(1<<i)) {
                bitset<501>bb;
                for(int j=1; j<=n; j++) {
                    if(b.test(j)) {
                        bb|=dp[ j ][ i ];
                    }
                }
                b=bb;
                if(!b.any())break;
            }
        }
        int tot=b.count( );
        if(tot==0)printf("0\n-1\n");
        else {
            printf("%d\n",tot);
            int f=0;
            for(int i=1; i<=n; i++) {
                if(!b.test(i))continue;
                if(f)printf(" ");
                printf("%d",i);
                f=1;
            }
            puts("");
        }
    }
    return 0;
}