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Submission #534063

# Submission time Handle Problem Language Result Execution time Memory
534063 2022-03-07T22:55:34 Z perchuts Portals (BOI14_portals) C++17
100 / 100
 274 ms 50748 KB 
#include <bits/stdc++.h>
#define maxn (int)(1e5+51)
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define ll long long
#define pb push_back
#define ull unsigned long long
#define ii pair<int,int>
#define iii tuple<int,int,int>
#define inf 2000000001
#define mod 1000000007 //998244353
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);

using namespace std;

template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }

char grid[1005][1005];
bool vis[1005][1005];
int walldist[1005][1005], dist[1005][1005], a[8] = {1,-1,0,0,0,0,1,-1}, n, m;
ii nearest[1005][1005][4];
vector<ii>walls;

bool valid(int x,int y){return x>=0&&y>=0&&x<=n+1&&y<=m+1;}

void bfs1(ii start){
    auto [u,v] = start;
    queue<ii>q;q.push(start);
    vis[u][v] = 1;
    while(!q.empty()){
        auto [x,y] = q.front();q.pop();
        for(int i=0;i<4;++i){
            int x2 = x+a[i],y2=y+a[i+4];
            if(valid(x2,y2)&&!vis[x2][y2]){
                vis[x2][y2]=1;
                if(grid[x2][y2]=='#')walls.pb({x2,y2});
                else q.push({x2,y2});
            }
        }
    }
}

void bfs2(){

    for(int i=1;i<=n;++i)
        for(int j=1;j<=m;++j)
            walldist[i][j] = inf;

    queue<ii>q;
    for(auto x:walls){
        q.push(x);
        walldist[x.first][x.second] = 0;
    }

    while(!q.empty()){
        auto [x,y] = q.front();q.pop();
        for(int i=0;i<4;++i){
            int x2 = x + a[i], y2 = y + a[i+4];
            if(valid(x2,y2)&&walldist[x2][y2]==inf){
                walldist[x2][y2] = walldist[x][y]+1;
                q.push({x2,y2});
            }
        }
    }
}

int b[8] = {0,1,0,-1,-1,0,1,0};
int bfs3(ii start,ii target){
    priority_queue<pair<int,ii>,vector<pair<int,ii>>,greater<pair<int,ii>>>pq;
    pq.push({0,start});
    for(int i=1;i<=n;++i)
        for(int j=1;j<=m;++j)
            dist[i][j] = inf;
    dist[start.first][start.second] = 0;
    while(!pq.empty()){
        auto [d,p] = pq.top();
        pq.pop();
        auto [x,y] = p;
        if(d>dist[x][y])continue;
        for(int i=0;i<4;++i){//normal adjacency
            int x2 = x + a[i], y2 = y + a[i+4];
            if(valid(x2,y2)&&grid[x2][y2]!='#'&&ckmin(dist[x2][y2],d+1)){
                pq.push({dist[x2][y2],{x2,y2}});
            }
        }        
        //now portal adjacency
        for(int i=0;i<4;++i){
            auto [x2,y2] = nearest[x][y][i];
            x2+=b[i],y2+=b[i+4];
            if(ckmin(dist[x2][y2],d+walldist[x][y]))pq.push({dist[x2][y2],{x2,y2}});
        }
    }
    return dist[target.first][target.second];
}

int main(){_
    cin>>n>>m;
    ii start,target;
    for(int i=1;i<=n;++i){
        for(int j=1;j<=m;++j){
            cin>>grid[i][j];
            if(grid[i][j]=='S')start={i,j};
            if(grid[i][j]=='C')target={i,j};
        }
    }
    for(int i=0;i<=n;++i)grid[i][0]=grid[i][m+1]='#';
    for(int j=0;j<=m;++j)grid[0][j]=grid[n+1][j]='#';
    bfs1(start);//find walls
    bfs2();//get distance from each open square to nearest wall

    //nearest: 0 => direita, 1=> subindo, 2=> esquerda, 3=>descendo
    
    for(int i=0;i<=n+1;++i){
        for(int j=m+1;~j;j--)nearest[i][j][0] = {i,(grid[i][j]=='#'?j:nearest[i][j+1][0].second)};
        for(int j=0;j<=m+1;++j)nearest[i][j][2] = {i,(grid[i][j]=='#'?j:nearest[i][j-1][2].second)};
    }
    for(int j=0;j<=m+1;++j){
        for(int i=0;i<=n+1;++i)nearest[i][j][1] = {(grid[i][j]=='#'?i:nearest[i-1][j][1].first),j};
        for(int i=n+1;~i;--i)nearest[i][j][3] = {(grid[i][j]=='#'?i:nearest[i+1][j][3].first),j};
    }

    cout<<bfs3(start,target)<<endl;   
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 332 KB Output is correct
2 Correct 1 ms 444 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 1 ms 448 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 332 KB Output is correct
10 Correct 1 ms 316 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 320 KB Output is correct
2 Correct 1 ms 460 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 0 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 1100 KB Output is correct
10 Correct 1 ms 1100 KB Output is correct
11 Correct 1 ms 1100 KB Output is correct
12 Correct 1 ms 1100 KB Output is correct
13 Correct 1 ms 1100 KB Output is correct
14 Correct 1 ms 332 KB Output is correct
15 Correct 1 ms 1092 KB Output is correct
16 Correct 0 ms 332 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 460 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 0 ms 460 KB Output is correct
5 Correct 8 ms 4688 KB Output is correct
6 Correct 9 ms 4688 KB Output is correct
7 Correct 10 ms 4684 KB Output is correct
8 Correct 5 ms 4792 KB Output is correct

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 460 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 1 ms 316 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 1100 KB Output is correct
10 Correct 1 ms 1100 KB Output is correct
11 Correct 1 ms 1100 KB Output is correct
12 Correct 1 ms 1100 KB Output is correct
13 Correct 1 ms 1100 KB Output is correct
14 Correct 7 ms 4688 KB Output is correct
15 Correct 9 ms 4688 KB Output is correct
16 Correct 9 ms 4812 KB Output is correct
17 Correct 9 ms 4684 KB Output is correct
18 Correct 10 ms 4696 KB Output is correct
19 Correct 9 ms 4432 KB Output is correct
20 Correct 10 ms 4428 KB Output is correct
21 Correct 7 ms 4772 KB Output is correct
22 Correct 8 ms 4688 KB Output is correct
23 Correct 9 ms 4688 KB Output is correct
24 Correct 8 ms 4428 KB Output is correct
25 Correct 0 ms 332 KB Output is correct
26 Correct 1 ms 1100 KB Output is correct
27 Correct 1 ms 332 KB Output is correct
28 Correct 5 ms 4664 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 0 ms 460 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 1 ms 448 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 444 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 1100 KB Output is correct
10 Correct 1 ms 1100 KB Output is correct
11 Correct 1 ms 1100 KB Output is correct
12 Correct 1 ms 1088 KB Output is correct
13 Correct 1 ms 1084 KB Output is correct
14 Correct 8 ms 4688 KB Output is correct
15 Correct 9 ms 4688 KB Output is correct
16 Correct 11 ms 4684 KB Output is correct
17 Correct 8 ms 4684 KB Output is correct
18 Correct 10 ms 4676 KB Output is correct
19 Correct 10 ms 4428 KB Output is correct
20 Correct 9 ms 4428 KB Output is correct
21 Correct 8 ms 4688 KB Output is correct
22 Correct 8 ms 4688 KB Output is correct
23 Correct 9 ms 4684 KB Output is correct
24 Correct 213 ms 49180 KB Output is correct
25 Correct 274 ms 43032 KB Output is correct
26 Correct 242 ms 42948 KB Output is correct
27 Correct 234 ms 42924 KB Output is correct
28 Correct 168 ms 50696 KB Output is correct
29 Correct 187 ms 50736 KB Output is correct
30 Correct 211 ms 50696 KB Output is correct
31 Correct 8 ms 4484 KB Output is correct
32 Correct 218 ms 42816 KB Output is correct
33 Correct 1 ms 332 KB Output is correct
34 Correct 1 ms 1100 KB Output is correct
35 Correct 190 ms 46764 KB Output is correct
36 Correct 1 ms 332 KB Output is correct
37 Correct 5 ms 4676 KB Output is correct
38 Correct 108 ms 50732 KB Output is correct
39 Correct 139 ms 50748 KB Output is correct