Submission #949023

#	Time	Username	Problem	Language	Result	Execution time	Memory
949023		MarwenElarbi	Portals (BOI14_portals)	C++17	70 / 100	1039 ms	18204 KiB

portals

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define vi vector<int>
#define ve vector
#define ll long long
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define onbit __builtin_popcount
#define ii pair<int,int>
#define vvi vector<vi>
#define vii vector<ii>
#define gii greater<ii>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define INF 1e18
#define eps 1e-7
#define eps1 1e-2
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MAX_A 1e5+5
using namespace std;
using namespace __gnu_pbds;
template <class T>
using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const ll MOD = 1e9+7;
const int nax = 1e3+5;
const int MAX_VAL = 1e6+1;
double PI=3.14159265359;
int arx[8]={1,0,0,-1,-1,-1, 1, 1};
int ary[8]={0,1,-1, 0, 1,-1,-1, 1};
void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
int n,m;
char grid[nax][nax];
bool can(int x,int y){
    if(x<0||y<0||x>=n||y>=m) return false;
    return grid[x][y]!='#';
}
ii dfs(int x,int y,ii pas){
    while(can(x+pas.fi,y+pas.se)){
        x+=pas.fi;
        y+=pas.se;
    }
    return {x,y};
}
int main(){
    optimise;
    
    cin>>n>>m;
    ii start;
    ii last;
    int dis[n][m][2];
    queue<ii> q;
    int b[n][m];
    memset(b,0,sizeof b);
    for (int i = 0; i < n; ++i)
    {
        for (int j = 0; j < m; ++j)
        {
            dis[i][j][0]=dis[i][j][1]=1e9;
            cin>>grid[i][j];
            b[i][j]=min(min(n-i,m-j),min(i+1,j+1));
            if(grid[i][j]=='C') last={i,j};
            if(grid[i][j]=='S') start={i,j};
            else if(grid[i][j]=='#') {
                q.push({i,j});
                b[i][j]=0;
            }
        }
    }
    while(!q.empty()){
        auto node=q.front();
        int d=b[node.fi][node.se];
        q.pop();
        for (int i = 0; i < 4; ++i)
        {
            int x=node.fi+arx[i];
            int y=node.se+ary[i];
            if(!can(x,y)) continue;
            if(b[x][y]>d+1){
                b[x][y]=d+1;
                q.push({x,y});
            }
        }
    }
    priority_queue<pair<ii,ii>,vector<pair<ii,ii>>,greater<pair<ii,ii>>> pq;
    pq.push({{0,0},start});
    dis[start.fi][start.se][0]=dis[start.fi][start.se][1]=0;
    while(!pq.empty()){
        ii node=pq.top().se;
        int type=pq.top().fi.se;
        int d=pq.top().fi.fi;
        if(node==last){
            cout << d <<endl;
            return 0;
        }
        pq.pop();
        if(type==1&&dis[node.fi][node.se][type]>=dis[node.fi][node.se][0]) continue;
        if(dis[node.fi][node.se][type]<d) continue;
        //cout <<node.fi<<" "<<node.se<<" "<<d<<" "<<type<<endl;
        for (int i = 0; i < 4; ++i)
        {
            int x=node.fi+arx[i];
            int y=node.se+ary[i];
            if(!can(x,y)) continue;
            int newd=d+1;
            if(dis[x][y][type]<=newd) continue;
            dis[x][y][type]=newd;
            if(type==0) dis[x][y][1]=min(dis[x][y][1],newd);
            pq.push({{newd,type},{x,y}});
        }
        if(type==0){
            for (int i = 0; i < 4; ++i)
            {
                ii pas={arx[i],ary[i]};
                ii to=dfs(node.fi,node.se,pas);
                /*ii inverse={-arx[i],-ary[i]};
                if(!can(inverse.fi+node.fi,inverse.se+node.se)){
                    int newd=d+1;
                    if(dis[to.fi][to.se][0]>newd){
                        dis[to.fi][to.se][0]=newd;
                        dis[to.fi][to.se][1]=min(dis[to.fi][to.se][1],newd);
                        pq.push({{newd,0},{to.fi,to.se}});
                    }
                }*/
                int newd=d+b[node.fi][node.se];
                if(dis[to.fi][to.se][0]>newd){
                    dis[to.fi][to.se][0]=newd;
                    pq.push({{newd,0},{to.fi,to.se}});
                }
            }
        }
    }
}

Compilation message (stderr)

portals.cpp: In function 'void setIO(std::string)':
portals.cpp:35:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
portals.cpp:36:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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