Submission #943245

#	Time	Username	Problem	Language	Result	Execution time	Memory
943245		salmon	Portals (BOI14_portals)	C++14	0 / 100	2 ms	12636 KiB

portals

#include <bits/stdc++.h>
using namespace std;

int R;
int C;
int x,y;
int gx,gy;
int sx,sy;
char c;
int lst[1100][1100];
int nextr[1100][1100];
int nextc[1100][1100];
int prevr[1100][1100];
int prevc[1100][1100];

int dw[1100][1100];
int d[1100][1100];


priority_queue<vector<int>,vector<vector<int>>,greater<vector<int>>> pq;
queue<vector<int>> q;

vector<pair<int,int>> bah = {{0,-1},{0,1},{1,0},{-1,0}};

bool valid(int i, int j){
    if(i >= 0 && i < R && 0 <= j && j < C) return true;
    return false;
}

int main(){
    scanf(" %d",&R);
    scanf(" %d",&C);

    for(int i = 0; i < R; i++){
        for(int j = 0; j < C; j++){
            scanf(" %c",&c);
            if(c == '#'){
                lst[i][j] = 1;
            }
            else{
                lst[i][j] = 0;
            }

            if(c == 'C'){
                gx = i;
                gy = j;
            }
            if(c == 'S'){
                sx = i;
                sy = j;
            }

            d[i][j] = -1;
            dw[i][j] = -1;
        }
    }

    for(int i = 0; i < R; i++){
        vector<int> s;

        for(int j = 0; j < C; j++){
            while(!s.empty() && lst[i][j] == 1){
                nextr[i][s.back()] = j;
                s.pop_back();
            }
            s.push_back(j);
        }

        while(!s.empty()){
            nextr[i][s.back()] = C;
            s.pop_back();
        }
    }

    for(int j = 0; j < C; j++){
        vector<int> s;

        for(int i = 0; i < R; i++){
            while(!s.empty() && lst[i][j] == 1){
                nextc[s.back()][j] = i;
                s.pop_back();
            }
            s.push_back(i);
        }

        while(!s.empty()){
            nextc[s.back()][j] = R;
            s.pop_back();
        }
    }


    for(int i = 0; i < R; i++){
        vector<int> s;

        for(int j = C - 1; j >= 0; j--){
            while(!s.empty() && lst[i][j] == 1){
                prevr[i][s.back()] = j;
                s.pop_back();
            }
            s.push_back(j);
        }

        while(!s.empty()){
            prevr[i][s.back()] = -1;
            s.pop_back();
        }
    }

    for(int j = 0; j < C; j++){
        vector<int> s;

        for(int i = R - 1; i >= 0; i--){
            while(!s.empty() && lst[i][j] == 1){
                prevc[s.back()][j] = i;
                s.pop_back();
            }
            s.push_back(i);
        }

        while(!s.empty()){
            prevc[s.back()][j] = -1;
            s.pop_back();
        }
    }

    for(int i = 0; i < R; i++){
        for(int j = 0; j < C; j++){
            if(lst[i][j] == 1) q.push({i,j,0});
        }
    }

    for(int i = 0; i < R; i++){
        q.push({i,0,1});
        q.push({i,C-1,1});
    }

    for(int i = 0; i < C; i++){
        q.push({0,i,1});
        q.push({R-1,i,1});
    }

    while(!q.empty()){
        vector<int> v = q.front();
        q.pop();
        int i = v[0];
        int j = v[1];

        if(dw[i][j] != -1) continue;

        dw[i][j] = v[2];

        for(pair<int,int> ii : bah){
            int ni = ii.first + i;
            int nj = ii.second + j;

            if(valid(ni,nj) && dw[i][j] == -1){
                q.push({ni,nj,v[2] + 1});
            }
        }
    }


    pq.push({0,sx,sy});
    //pq.push({0,sx,sy,false});

    while(!pq.empty()){
        vector<int> v = pq.top();
        pq.pop();

        int i = v[1];
        int j = v[2];
        int de = v[0];

        if(d[i][j] != -1) continue;
        if(lst[i][j] == 1) continue;

        d[i][j] = de;

        for(pair<int,int> ii : bah){
            int ni = ii.first + i;
            int nj = ii.second + j;

            if(valid(ni,nj) && lst[ni][nj] != 1 && d[ni][nj] == -1){
                pq.push({de+1,ni,nj});
            }
        }

        if(d[i][prevr[i][j] + 1] == -1) pq.push({de + dw[i][j],i,prevr[i][j] + 1});
        if(d[i][nextr[i][j] - 1] == -1) pq.push({de + dw[i][j],i,nextr[i][j] - 1});
        if(d[prevc[i][j] + 1][j] == -1) pq.push({de + dw[i][j],prevc[i][j] + 1,j});
        if(d[nextc[i][j] - 1][j] == -1) pq.push({de + dw[i][j],nextc[i][j] - 1,j});
    }

    /*for(int i = 0; i < R; i++){
        for(int j = 0; j < C; j++){
            printf("%d ",dw[i][j]);
        }
        printf("\n");
    }*/

    printf("%d",d[gx][gy]);

}
/*
5 4
G#.#
.#.#
...#
S..#
....
*/

Compilation message (stderr)

portals.cpp: In function 'int main()':
portals.cpp:31:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |     scanf(" %d",&R);
      |     ~~~~~^~~~~~~~~~
portals.cpp:32:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     scanf(" %d",&C);
      |     ~~~~~^~~~~~~~~~
portals.cpp:36:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |             scanf(" %c",&c);
      |             ~~~~~^~~~~~~~~~

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