added shortest path in binary matrix problem

Author: Kowsihan-sk

Graph/(LEETCODE) Shortest_path_in_binary_matrix.cpp

@@ -0,0 +1,38 @@
+class Solution {
+public:
+    
+    int shortestPathBinaryMatrix(vector<vector<int>>& grid) {
+        int n = grid.size(), len = 1;
+        if(grid[0][0] == 1 || grid[n-1][n-1] == 1) return -1;
+        if(n==1) return 1;
+        
+        vector<vector<int>> off = {{0,1},{0,-1},{1,0},{-1,0},{1,1},{-1,-1},{1,-1},{-1,1}};
+        queue<pair<int,int>> q;
+        q.push({0,0});
+        grid[0][0] = 1;
+        
+        int sz, row, col, i, j;
+        
+        while(!q.empty()){
+            sz = q.size();
+            for(i = 0; i < sz; i++){
+                row = q.front().first, col = q.front().second;
+                q.pop();
+                
+                if(row == n-1 && col == n-1) return len;
+                
+                for(j = 0; j < 8; j++){
+                    int x = row + off[j][0], y = col + off[j][1];
+                    if(x >= 0 && y >= 0 && x < n && y < n && grid[x][y] == 0){
+                        grid[x][y] = 1;
+                        q.push({x,y});
+                    }
+                }
+                
+            }
+            len++;
+        }
+        
+        return -1;
+    }
+};