Submission #751270

#	Time	Username	Problem	Language	Result	Execution time	Memory
751270		irmuun	Portals (BOI14_portals)	C++17	0 / 100	1 ms	444 KiB

portals

#include<bits/stdc++.h>

using namespace std;
 
#define pb push_back
#define ll long long
#define ff first
#define ss second
#define all(s) s.begin(),s.end()

int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    int r,c;
    cin>>r>>c;
    string s[r];
    vector<pair<int,int>>adj[r][c];
    int sx,sy,cx,cy;
    for(int i=0;i<r;i++){
        cin>>s[i];
        vector<int>v;
        v.pb(-1);
        for(int j=0;j<c;j++){
            if(s[i][j]=='S'){
                sx=i;
                sy=j;
            }
            if(s[i][j]=='C'){
                cx=i;
                cy=j;
            }
            if(s[i][j]=='#'){
                v.pb(j);
            }
        }
        v.pb(r);
        for(int j=0;j<v.size()-1;j++){
            if(v[j]+1!=v[j+1]){
                adj[i][v[j]+1].pb({i,v[j+1]-1});
                adj[i][v[j+1]-1].pb({i,v[j]+1});
            }
        }
    }
    for(int j=0;j<c;j++){
        vector<int>v;
        v.pb(-1);
        for(int i=0;i<r;i++){
            if(s[i][j]=='#'){
                v.pb(i);
            }
        }
        v.pb(r);
        for(int i=0;i<v.size()-1;i++){
            if(v[i]+1!=v[i+1]){
                adj[v[i]+1][j].pb({v[i+1]-1,j});
                adj[v[i+1]-1][j].pb({v[i]+1,j});
            }
        }
    }
    vector<int>dx={1,-1,0,0};
    vector<int>dy={0,0,1,-1};
    for(int i=0;i<r;i++){
        for(int j=0;j<c;j++){
            for(int k=0;k<4;k++){
                int x=i+dx[k],y=j+dy[k];
                if(x<0||x>=r||y<0||y>=c||s[x][y]=='#') continue;
                adj[i][j].pb({x,y});
            }
        }
    }
    int dist[r][c];
    memset(dist,-1,sizeof(dist));
    queue<pair<int,int>>q;
    q.push({sx,sy});
    dist[sx][sy]=0;
    while(!q.empty()){
        int x=q.front().ff,y=q.front().ss;
        q.pop();
        for(auto [i,j]:adj[x][y]){
            if(dist[i][j]==-1){
                dist[i][j]=dist[x][y]+1;
                q.push({i,j});
            }
        }
    }
    cout<<dist[cx][cy];
}

Compilation message (stderr)

portals.cpp: In function 'int main()':
portals.cpp:36:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |         for(int j=0;j<v.size()-1;j++){
      |                     ~^~~~~~~~~~~
portals.cpp:52:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |         for(int i=0;i<v.size()-1;i++){
      |                     ~^~~~~~~~~~~
portals.cpp:74:17: warning: 'sy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   74 |     dist[sx][sy]=0;
      |     ~~~~~~~~~~~~^~
portals.cpp:74:17: warning: 'sx' may be used uninitialized in this function [-Wmaybe-uninitialized]
portals.cpp:85:22: warning: 'cy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   85 |     cout<<dist[cx][cy];
      |                      ^
portals.cpp:85:22: warning: 'cx' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 1: 0 / 11
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 19
• Subtask 5: 0 / 30