Time: 8 ms (99.58%), Space: 12.6 MB (86.28%) - LeetHub

Author: JanaSabuj

snakes-and-ladders/snakes-and-ladders.cpp

@@ -0,0 +1,63 @@
+class Solution {
+public:
+    pair<int,int> func(int x, int n){
+        int r = x / n;
+        int c = x % n;
+        
+        int row = n - 1 - r;
+        int col = (r % 2 == 0) ? c : (n - 1 - c);
+        
+        return {row,col};        
+    }
+    
+    int snakesAndLadders(vector<vector<int>>& board) {
+        
+        int n = board.size();
+        
+        queue<int> q;
+        vector<int> visited(n * n + 1, 0);
+        
+        q.push(1);
+        visited[1] = 1;
+        
+        int steps = -1;
+                
+        while(!q.empty()){            
+            int sz = q.size();            
+            steps++;
+            
+            while(sz--){                            
+                int x = q.front();
+                q.pop();
+                
+                if(x == n * n)
+                    return steps;
+
+                for(int i = 1; i <= 6; i++){
+                    int v = x + i;
+                    if(v > n * n) break;                                                                            
+                        pair<int,int> c = func(v - 1, n);
+                        int a = c.first, b = c.second;
+                    
+                        if(board[a][b] == -1){
+                            if(!visited[v]){
+                                q.push(v);
+                                visited[v] = 1;
+                            }
+                        }
+                    
+                        else{                        
+                            if(!visited[board[a][b]]){
+                                q.push(board[a][b]);
+                                visited[board[a][b]] = 1;
+                                // visited[v] = 1;
+                            }
+                        }
+                    
+                }
+            }
+        }
+        
+        return -1;
+    }
+};