Submission #136044

#	Time	Username	Problem	Language	Result	Execution time	Memory
136044		Blagojce	Portals (BOI14_portals)	C++11	20 / 100	6 ms	1144 KiB

portals

#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x),end(x)
#define mp make_pair

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
ll const inf = 1e9;
ll const mod = 1e9 + 7;
ld const eps = 1e-9;

int main()
{
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        int n, m;
        cin >> n >> m;
        char mapa[n][m];
        int sr, sc;
        int er, ec;
        fr(i, 0, n){
                fr(j, 0, m){
                        cin >> mapa[i][j];
                        if(mapa[i][j] == 'S'){
                                sr = i;
                                sc = j;
                                mapa[i][j] = '.';
                        }
                        else if(mapa[i][j] == 'C'){
                                er = i;
                                ec = j;
                                mapa[i][j] = '.';
                        }
                }
        }


        int toleft[n][m];
        int toright[n][m];
        fr(i, 0, n){
                int last = -1;
                fr(j, 0, m){
                        if(mapa[i][j] == '.' && last == -1){
                                last = j;
                        }
                        else if(mapa[i][j] == '#') last = -1;
                        toleft[i][j] = last;
                }
                last = -1;
                for(int j = m - 1; j >= 0; j --){
                        if(mapa[i][j] =='.' && last == -1){
                                last = j;
                        }
                        else if(mapa[i][j] == '#') last = -1;
                        toright[i][j] = last;
                }
        }
        int toup[n][m];
        int todown[n][m];
        fr(j, 0, m){
                int last = -1;
                fr(i, 0, n){
                        if(mapa[i][j] == '.' && last == -1){
                                last = i;
                        }
                        else if(mapa[i][j] == '#') last = -1;
                        toup[i][j] = last;
                }
                last = -1;
                for(int i = n - 1; i >= 0; i --){
                        if(mapa[i][j] == '.' && last == -1){
                                last = i;
                        }
                        else if(mapa[i][j] == '#') last = -1;
                        todown[i][j] = last;
                }
        }

        bool portal[n][m];
        memset(portal, false, sizeof(portal));
        fr(i, 0, n){
                fr(j, 0, m){
                        if(i == 0 || i == n - 1 || j == 0 || j == m - 1 || mapa[i + 1][j] == '#' || mapa[i - 1][j] == '#' || mapa[i][j + 1] == '#' || mapa[i][j - 1] == '#'){
                                portal[i][j] = true;
                        }
                }
        }
        queue<pair<int,pii> > Q;
        Q.push(mp(0,mp(sr,sc)));
        bool vis[n][m];
        memset(vis, false, sizeof(vis));
        vis[sr][sc] = true;
        fr(i, 0, n){
                fr(j, 0, m){
                        if(mapa[i][j] == '#') vis[i][j] = true;
                }
        }
        while(!Q.empty()){
                int r = Q.front().nd.st;
                int c = Q.front().nd.nd;
                int d = Q.front().st;
                if(r == er && c == ec){
                        cout << d <<endl;
                        return 0;
                }
                Q.pop();
                if(r + 1 < n && !vis[r + 1][c]){
                        vis[r + 1][c] = true;
                        Q.push({d + 1,{r + 1, c}});
                }
                if(r - 1 >= 0 && !vis[r - 1][c]){
                        vis[r - 1][c] = true;
                        Q.push({d + 1,{r - 1, c}});
                }
                if(c + 1 < m && !vis[r][c + 1]){
                        vis[r][c + 1] = true;
                        Q.push({d + 1,{r, c + 1}});
                }
                if(c - 1 >= 0 && !vis[r][c - 1]){
                        vis[r][c - 1] = true;
                        Q.push({d + 1,{r, c - 1}});
                }
                if(portal[r][c]){
                        if(toleft[r][c] != -1 && !vis[r][toleft[r][c]]){
                                vis[r][toleft[r][c]] = true;
                                Q.push(mp(d + 1,mp(r, toleft[r][c])));
                        }
                        if(toright[r][c] != -1 && !vis[r][toright[r][c]]){
                                vis[r][toright[r][c]] = true;
                                Q.push(mp(d + 1,mp(r, toright[r][c])));
                        }
                        if(toup[r][c] != -1 && !vis[toup[r][c]][c]){
                                vis[toup[r][c]][c] = true;
                                Q.push(mp(d + 1,mp(toup[r][c], c)));
                        }
                        if(todown[r][c] != -1 && !vis[todown[r][c]][c]){
                                vis[todown[r][c]][c] = true;
                                Q.push(mp(d + 1,mp(todown[r][c], c)));
                        }
                }

        }

        cout << -1 << endl;
        return 0;
}

Compilation message (stderr)

portals.cpp: In function 'int main()':
portals.cpp:98:21: warning: 'sc' may be used uninitialized in this function [-Wmaybe-uninitialized]
         vis[sr][sc] = true;
         ~~~~~~~~~~~~^~~~~~
portals.cpp:98:21: warning: 'sr' may be used uninitialized in this function [-Wmaybe-uninitialized]
portals.cpp:108:17: warning: 'er' may be used uninitialized in this function [-Wmaybe-uninitialized]
                 if(r == er && c == ec){
                 ^~
portals.cpp:108:28: warning: 'ec' may be used uninitialized in this function [-Wmaybe-uninitialized]
                 if(r == er && c == ec){
                    ~~~~~~~~^~~~~~~~~~

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