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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int n, m;
  5. char grid[1005][1005];
  6. int vis[1005][1005];
  7. int level[1005][1005];
  8. pair<int,int> par[1005][1005];
  9.  
  10. vector<pair<int, int>> b = {{0, 1}, {0, -1}, {-1, 0}, {1, 0}};
  11.  
  12. bool valid(int i, int j) {
  13.     return !(i < 0 || i >= n || j < 0 || j >= m || grid[i][j] == '#');
  14. }
  15.  
  16. void bfs(int si, int sj) {
  17.     queue<pair<int, int>> q;
  18.     q.push({si, sj});
  19.     vis[si][sj] = true;
  20.     level[si][sj] = 0;
  21.  
  22.     while(!q.empty()) {
  23.         int pi = q.front().first;
  24.         int pj = q.front().second;
  25.         q.pop();
  26.  
  27.         for (int i = 0; i < 4; i++) {
  28.             int ci = pi + b[i].first;
  29.             int cj = pj + b[i].second;
  30.  
  31.             if(valid(ci, cj) && !vis[ci][cj]) {
  32.                 q.push({ci, cj});
  33.                 vis[ci][cj] = true;
  34.                 level[ci][cj] = level[pi][pj] + 1;
  35.                 par[ci][cj] = {pi,pj};
  36.             }
  37.         }
  38.     }
  39. }
  40.  
  41.  
  42.  
  43. int main() {
  44.     cin >> n >> m;
  45.     int si = -1, sj = -1, di = -1, dj = -1;
  46.  
  47.     memset(vis, false, sizeof(vis));
  48.     memset(level, -1, sizeof(level));
  49.     memset(par, -1, sizeof(par));
  50.  
  51.  
  52.  
  53.  
  54.     for(int i = 0; i < n; i++) {
  55.         for(int j = 0; j < m; j++) {
  56.             cin >> grid[i][j];
  57.  
  58.             if(grid[i][j] == 'R') {
  59.                 si = i;
  60.                 sj = j;
  61.             }
  62.  
  63.             if(grid[i][j] == 'D') {
  64.                 di = i;
  65.                 dj = j;
  66.             }
  67.         }
  68.     }
  69.  
  70.  
  71.     bfs(si, sj);
  72.  
  73.     pair<int,int> dst = {di, dj};
  74.  
  75.     while(dst.first != -1 && dst.second != -1) {
  76.  
  77.         if(grid[dst.first][dst.second] != 'R' && grid[dst.first][dst.second] != 'D') {
  78.             grid[dst.first][dst.second]='X';
  79.         }
  80.  
  81.         dst = par[dst.first][dst.second];
  82.     }
  83.  
  84.     for(int i = 0; i < n; i++) {
  85.         for(int j = 0; j < m; j++) {
  86.             cout << grid[i][j];
  87.         }
  88.         cout << endl;
  89.     }
  90.  
  91.     return 0;
  92. }
  93.  
Success #stdin #stdout 0.01s 19312KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/9Nq5Mu
language:
C++ (gcc 8.3)
created:
4 days ago
visibility:
public

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