Submission #151187

#	Time	Username	Problem	Language	Result	Execution time	Memory
151187		imyujin	Trip to the Galapagos Islands (FXCUP4_island)	C++17	31 / 100	5020 ms	24360 KiB

island

#include "island.h"
#include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> pii;

#define eb emplace_back
#define allv(v) ((v).begin()),((v).end())

const int SQRTN = 280;
const int MAXN = 100010;
const int MAXM = 300010;
const int MX = 1 << 17;

int N, M;
vector<int> node[MAXN], ed[MAXN];
int uni[MAXN];
vector<int> idx[MAXN];
int mem[SQRTN][MAXN];
int bigidx[MAXN];
int seg[2 * MX];

int guni(int x) { return x == uni[x] ? x : guni(uni[x]); }

void mkseg(int idx, int l, int r) {
	if(l == r) seg[idx] = ed[0][l];
	else {
		int m = (l + r) / 2;
		mkseg(idx * 2, l, m);
		mkseg(idx * 2 + 1, m + 1, r);
		seg[idx] = min(seg[idx * 2], seg[idx * 2 + 1]);
	}
}

int gseg(int idx, int l, int r, int x, int y) {
	if(x <= l && r <= y) return seg[idx];
	else if(r < x || y < l) return M;
	int m = (l + r) / 2;
	return min(gseg(idx * 2, l, m, x, y), gseg(idx * 2 + 1, m + 1, r, x, y));
}
int gseg(int x, int y) { return gseg(1, 0, N - 2, x, y); }

void Init(int K, vector<int> F, vector<int> S, vector<int> E){
	N = F.size();
	M = S.size();
	for(int i = 0; i < N; i++) {
		uni[i] = i;
		node[i].eb(i);
	}

	for(int i = M - 1; i >= 0; i--) {
		S[i] = guni(S[i]);
		E[i] = guni(E[i]);
		if(S[i] == E[i]) continue;
		if(node[S[i]].size() < node[E[i]].size()) swap(S[i], E[i]);
		node[S[i]].insert(node[S[i]].end(), allv(node[E[i]]));
		ed[S[i]].eb(i);
		ed[S[i]].insert(ed[S[i]].end(), allv(ed[E[i]]));
		uni[E[i]] = S[i];
	}
	for(int i = 0; i < N; i++) if(i == uni[i]) {
		node[0] = node[i];
		ed[0] = ed[i];
	}
	for(int i = 0; i < N; i++) idx[F[node[0][i]]].eb(i);
	mkseg(1, 0, N - 2);

	int cnt = 0;
	for(int i = 0; i < K; i++) {
		if(idx[i].size() > SQRTN) {
			bigidx[i] = cnt++;
			int mn = M;
			for(int j = idx[i][0] + 1; j < N; j++) {
				mn = min(mn, ed[0][j - 1]);
				if(F[node[0][j]] == i) mn = M;
				else mem[bigidx[i]][F[node[0][j]]] = max(mem[bigidx[i]][F[node[0][j]]], mn);
			}
			mn = M;
			for(int j = idx[i].back() - 1; j >= 0; j--) {
				mn = min(mn, ed[0][j]);
				if(F[node[0][j]] == i) mn = M;
				else mem[bigidx[i]][F[node[0][j]]] = max(mem[bigidx[i]][F[node[0][j]]], mn);
			}
		}
		else bigidx[i] = -1;
	}
}

int Separate(int A, int B){
	if(bigidx[A] != -1) return mem[bigidx[A]][B] + 1;
	if(bigidx[B] != -1) return mem[bigidx[B]][A] + 1;

	int ans = 0;
	int pa = 0, pb = 0;
	while(pa < idx[A].size() && pb < idx[B].size()) {
		if(idx[A][pa] < idx[B][pb]) {
			ans = max(ans, gseg(idx[A][pa], idx[B][pb] - 1));
			pa++;
		}
		else {
			ans = max(ans, gseg(idx[B][pb], idx[A][pa] - 1));
			pb++;
		}
	}
	return ans + 1;
}

Compilation message (stderr)

island.cpp: In function 'int Separate(int, int)':
island.cpp:95:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(pa < idx[A].size() && pb < idx[B].size()) {
        ~~~^~~~~~~~~~~~~~~
island.cpp:95:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(pa < idx[A].size() && pb < idx[B].size()) {
                              ~~~^~~~~~~~~~~~~~~

• Subtask 1: 31 / 31
• Subtask 2: 0 / 39
• Subtask 3: 0 / 30