Submission #980775

#	Time	Username	Problem	Language	Result	Execution time	Memory
980775		TheEpicCowOfLife	Island Hopping (JOI24_island)	C++17	35 / 100	8 ms	1752 KiB

island

#include <bits/stdc++.h>

#include "island.h"

using namespace std;

int N;

vector<int> g[305];

int d[305][305];

int ua[305];
vector<int> ug[305];

void dfs(int x, int par, int root, int depth){
  d[root][x] = depth;
  d[x][root] = depth;
  for (int tgt : g[x]){
    if (tgt == par) continue;
    dfs(tgt,x,root,depth+1);
  }
}

int f(int x){
  if (ua[x] == x) return x;
  return ua[x] = f(ua[x]);
}


// "All neighbours known"
bool ann[305];

int gi[305];

void merge(int x, int y){
  int fx = f(x);
  int fy = f(y);
  if (f(x) == f(y)){
    return;
  }
  if (ug[fx].size() > ug[fy].size()){
    swap(fx,fy);
    swap(x,y);
  }
  g[x].push_back(y);
  g[y].push_back(x);

  answer(x,y);
  if (g[x].size() == N-1){
    ann[x] = true;
  }
  if (g[y].size() == N-1){
    ann[y] = true;
  }
  for (int tgt : ug[fx]){
    ug[fy].push_back(tgt);
    dfs(tgt,-1,tgt,0);
  }
  ua[fx] = fy;
  ug[fx].clear();
}

int num_non_ann[305];
queue<int> to_expand;

void solve(int n, int L) {
  N = n;
  for (int i = 1; i <= N; i++){
    ug[i].push_back(i);
    ua[i] = i;
    gi[i] = 1;
  }

  for (int i = N; i > 1; i--){
    int ret = query(i,1);
    merge(i,ret);
  }
  ann[1] = true;

  for (int cur_ann = 1; cur_ann < N; cur_ann++){
    while (true){
      bool found_to_expand = false;
      for (int j = 1; j <= N; j++){
        if (ann[j]) continue;
        bool can_expand = true;
        for (int tgt: g[j]){
          if (!ann[tgt]) {
            can_expand = false;
            break;
          }
        }
        if (can_expand){
          found_to_expand = true;
          int ret = query(j,++gi[j]);
          if (d[ret][j] == 2){
            ann[j] = true;
          }
          else{
            merge(ret,j);
          }
        }
      }
      if (!found_to_expand) break;
    }
    ann[cur_ann+1] = true;
  }
  // int variable_example = query(1, 1);
  // for (int i = 2; i <= N; i++) {
  //   answer(1, i);
  // }


}

Compilation message (stderr)

island.cpp: In function 'void merge(int, int)':
island.cpp:50:19: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   50 |   if (g[x].size() == N-1){
      |       ~~~~~~~~~~~~^~~~~~
island.cpp:53:19: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   53 |   if (g[y].size() == N-1){
      |       ~~~~~~~~~~~~^~~~~~

• Subtask 1: 2 / 2
• Subtask 2: 4 / 4
• Subtask 3: 7 / 7
• Subtask 4: 9 / 9
• Subtask 5: 13 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 22
• Subtask 8: 0 / 28