Submission #963460

#	Time	Username	Problem	Language	Result	Execution time	Memory
963460		kilkuwu	Game (APIO22_game)	C++17	60 / 100	4070 ms	39176 KiB

game

#include "game.h"

#include <bits/stdc++.h>

int n, k;

constexpr int N = 3e5 + 5;

int can_reach[N]; // can_reach from k -> 0
int be_reached[N]; // be reached from 0 -> k

std::vector<int> adj[N];
std::vector<int> radj[N];

void add_edge(int u, int v) {
  adj[u].push_back(v);
  radj[v].push_back(u);
}

void init(int _n, int _k) {
  n = _n, k = _k;
  for (int i = 0; i < k; i++) {
    can_reach[i] = i; // it can reach i -> k - 1
    be_reached[i] = i + 1; // can be reach from 0 -> i
  }
  for (int i = k; i < n; i++) {
    can_reach[i] = k; // can't reach any
    be_reached[i] = 0; // can't be reached by any
  }

  for (int i = 0; i + 1 < k; i++) {
    add_edge(i, i + 1);
  }
}

void update_can_reach(int u, int val) {
  if (can_reach[u] <= val) { // reach from can_reach[u] -> k - 1 
    return; // we don't care
  }
  can_reach[u] = val;
  for (int v : radj[u]) {
    update_can_reach(v, val);
  }
}

void update_be_reached(int u, int val) {
  if (be_reached[u] >= val) { // can be reached from 0 -> be_reached - 1
    return;
  }

  be_reached[u] = val;
  for (int v : adj[u]) {
    update_be_reached(v, val);
  }
}

int add_teleporter(int u, int v) {
  if (can_reach[v] < be_reached[u]) {
    return 1; 
  }
  update_can_reach(u, can_reach[v]);
  update_be_reached(v, be_reached[u]);
  add_edge(u, v);
  return 0;
}

• Subtask 1: 2 / 2
• Subtask 2: 10 / 10
• Subtask 3: 18 / 18
• Subtask 4: 30 / 30
• Subtask 5: 0 / 40