Submission #1111043

#	Time	Username	Problem	Language	Result	Execution time	Memory
1111043		sktodow	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	785 ms	221440 KiB

tracks

#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
     
#define int long long int
#define pb push_back
#define mid (l+(r-l)/2)
#define f first
#define s second
const int N=2e5+5;
const int MOD=1e9+7;
const long long inf=INT64_MAX;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
 
void io(string name = ""){ 
    freopen((name+".in").c_str(), "r", stdin);
    freopen((name+".out").c_str(), "w", stdout);
}
 
int x[4]={-1,0,1,0};
int y[4]={0,-1,0,1};
 
int n,m;
 
int32_t main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
    
    cin>>n>>m;
    vector<vector<char>>v(n,vector<char>(m));
    vector<vector<int>>dep(n,vector<int>(m,0));
    for(int i=0;i<n;i++){
        for(int j=0;j<m;j++){
            cin>>v[i][j];
        }
    }
    deque<array<int,2>>q;
    int ans=0;
    q.push_back({0,0});
    dep[0][0]=1;
    while(q.size()){
        int a=q.front()[0],b=q.front()[1];
        q.pop_front();
        ans=max(ans,dep[a][b]);
        for(int k=0;k<4;k++){
            int i=a+x[k],j=b+y[k];
            if(((i>=0&&i<n)&&(j>=0&&j<m)&&v[i][j]!='.')&&dep[i][j]==0){
                if(v[a][b]==v[i][j]){dep[i][j]=dep[a][b];q.push_front({i,j});}
                else{dep[i][j]=dep[a][b]+1;q.push_back({i,j});}
            }
        }
    }
    cout<<ans;
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'void io(std::string)':
tracks.cpp:17:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |     freopen((name+".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:18:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     freopen((name+".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70