Submission #18198611

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Source Code Expand

#include <iostream>
#include <string>
#include <cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<iomanip>
#include<bitset>
#define _USE_MATH_DEFINES
#include <math.h>
#include <functional>
#include<complex>
#include<cassert>
#include<random>
using namespace std;
#include<atcoder/all>
using namespace atcoder;


#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)

typedef long long ll;
const ll INF = 1e17;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
	if (a > b) { return a; }
	return b;
}

ll min(ll a, ll b) {
	if (a > b) { return b; }
	return a;
}

ll gcd(ll a, ll b) {
	if (b == 0) { return a; }
	if (a < b) { return gcd(b, a); }
	return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

struct edge {
	ll ind;
	ll fr;
	ll to;
	ll d;
};

using mint = modint;

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

vmint f, finv, inv;

void cominit(ll N) {
	ll MOD = modint::mod();//デフォルトが998244353に注意

	f.assign(N + 1, 1);
	finv.assign(N + 1, 1);
	inv.assign(N + 1, 1);
	inv[1] = 1;

	repn(i, N) {
		f[i] = f[i - 1] * i;
		if (i > 1)inv[i] = -inv[MOD % i] * (MOD / i);
		finv[i] = finv[i - 1] * inv[i];
	}
}

mint com(ll a, ll b) {
	if (a < 0 || b < 0 || a < b) { return 0; }
	return f[a] * finv[b] * finv[a - b];
}


/////////////////////////////////////


int main() {
	ll N, M;
	cin >> N >> M;
	dsu d(N + 1);

	vll par(N + M + 1);
	vll rt(N + 1);
	repn(i, N + M)par[i] = i;
	repn(i, N)rt[i] = i;

	repn(i, M) {
		ll a, b;
		cin >> a >> b;
		a = d.leader(a);
		b = d.leader(b);
		if (a == b) { continue; }
		par[rt[a]] = N + i;
		par[rt[b]] = N + i;
		
		d.merge(a, b);
		rt[d.leader(a)] = N + i;
	}

	vll ht(N + M + 1,0);
	for (ll i = N + M; i >= 1; i--) {
		ht[i] = ht[par[i]] + 1;
	}

	vvll dob(20, vll(N + M + 1, 0));

	repn(i, N + M)dob[0][i] = par[i];
	repn(j, 19)repn(i, N + M) {
		dob[j][i] = dob[j - 1][dob[j - 1][i]];
	}

	ll Q;
	cin >> Q;
	repn(q, Q) {
		ll x, y;
		cin >> x >> y;
		if (ht[x] < ht[y]) { swap(x, y); }

		ll dif = ht[x] - ht[y];
		rep(k, 20) {
			if ((dif >> k) & 1) { x = dob[k][x]; }
		}

		if (x == y) { cout << x - N << endl; continue; }
		for (ll k = 19; k >= 0; k--) {
			if (dob[k][x] != dob[k][y]) {
				x = dob[k][x];
				y = dob[k][y];
			}
		}

		if (par[x] != par[y]) { cout << -1 << endl; }
		else { cout << par[x]-N << endl; }
		
	}

}

Submission Info

Judge Result