Submission #925357

#	Time	Username	Problem	Language	Result	Execution time	Memory
925357		anton	Ideal city (IOI12_city)	C++17	32 / 100	1098 ms	2908 KiB

city

#include<bits/stdc++.h>

using namespace std;
#define pii pair<int, int>
#define ll long long

pii delta[4] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
pii add(pii lh, pii rh){
  return {lh.first+rh.first, lh.second+rh.second};
}
vector<int> block_list;
vector<vector<int>> adj;
map<pii, int> blocks;

bool check_presence(pii pos){
  if(blocks.find(pos)!= blocks.end()){
    return true;
  }
  return false;
}

vector<pii> get_adj(pii pos){
  vector<pii> res;
  for(int i = 0; i<4; i++){
    pii pos2 = add(pos, delta[i]);
    if(check_presence(pos2)){
      res.push_back(pos2);
    }
  }
  return res;
}

void BFS(int origin){
  for(int i = 0; i<block_list.size(); i++){
    block_list[i] =-1;
  }
  block_list[origin] = 0;
  queue<pair<int, int>> q;

  q.push({origin, 0});

  while(q.size()>0){
    auto cur = q.front();
    auto u = cur.first;
    auto d= cur.second;
    q.pop();
    for(auto v: adj[u]){
      if(block_list[v] == -1){
        block_list[v]= d+1;
        q.push({v, d+1});
      }
    }
  }
}
const long long mod = 1000000000;

int DistanceSum(int N, int *X, int *Y) {


  for(int i = 0; i<N; i++){
    blocks[{X[i], Y[i]}] = i;
  }
  block_list.resize(N, -1);
  adj.resize(N);

  for(int i = 0; i<N; i++){
    for(auto v: get_adj({X[i], Y[i]})){
      adj[i].push_back(blocks[v]);
    }
  }

  long long res = 0;
  for(int i = 0; i<N; i++){
    BFS(blocks[{X[i], Y[i]}]);

    for(int i = 0; i<N; i++){
      res = res + block_list[i];
    }
  }
  res/=2;
  return res%mod;

}

Compilation message (stderr)

city.cpp: In function 'void BFS(int)':
city.cpp:34:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |   for(int i = 0; i<block_list.size(); i++){
      |                  ~^~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 21 / 21
• Subtask 3: 0 / 23
• Subtask 4: 0 / 45