Submission #496543

#	Time	Username	Problem	Language	Result	Execution time	Memory
496543		600Mihnea	Cats or Dogs (JOI18_catdog)	C++17	38 / 100	3084 ms	6508 KiB

catdog

#include "catdog.h"
#include <bits/stdc++.h>

using namespace std;


const int N = (int) 1e5 + 7;
const int INF = (int) 1e9 + 7;
int n;
int par[N];
int dp1[N];
int dp2[N];
int cost1[N];
int cost2[N];
vector<int> g[N];

void build(int a, int p = 0) {
  par[a] = p;
  vector<int> kids;
  for (auto &b : g[a]) {
    if (b != p) {
      kids.push_back(b);
      build(b, a);
    }
  }
  g[a] = kids;
}

void dfs(int a) {
  dp1[a] = 0;
  dp2[a] = 0;
  for (auto &b : g[a]) {
    dfs(b);
    dp1[a] += min(dp1[b], 1 + dp2[b]);
    dp2[a] += min(dp2[b], 1 + dp1[b]);
  }
  dp1[a] += cost1[a];
  dp2[a] += cost2[a];
}

void initialize(int nn, std::vector<int> edgesA, std::vector<int> edgesB) {
  n = nn;
  for (int i = 0; i < n - 1; i++) {
    int a = edgesA[i];
    int b = edgesB[i];
    g[a].push_back(b);
    g[b].push_back(a);
  }
  build(1);
}

void upd(int a, int sgn) {
  if (!a) {
    return;
  }
  int p = par[a];
  dp1[p] += sgn * min(dp1[a], 1 + dp2[a]);
  dp2[p] += sgn * min(dp2[a], 1 + dp1[a]);
  upd(p, sgn);
}

void change(int v, int c1, int c2) {
  cost1[v] = c1;
  cost2[v] = c2;
  dfs(1);
}

int cat(int v) {
  change(v, INF, 0);
  return min(dp1[1], dp2[1]);
}

int dog(int v) {
  change(v, 0, INF);
  return min(dp1[1], dp2[1]);
}

int neighbor(int v) {
  change(v, 0, 0);
  return min(dp1[1], dp2[1]);
}

• Subtask 1: 8 / 8
• Subtask 2: 30 / 30
• Subtask 3: 0 / 62