Create 1568-minimum-number-of-days-to-disconnect-island.java

Author: sujal-goswami

Diff for: java/1568-minimum-number-of-days-to-disconnect-island.java

@@ -0,0 +1,57 @@
+/*------------------------------------
+  Time complexity: (m*n)^2
+  Space complexity: (m*n)
+------------------------------------*/  
+
+class Solution {
+    public int minDays(int[][] grid) {
+        if(count_lands(grid) != 1)
+            return 0;
+
+        for(int r = 0; r < grid.length; r++){
+            for(int c = 0; c < grid[r].length; c++){
+                if(grid[r][c] == 0)
+                    continue;
+
+                grid[r][c] = 0;
+                if(count_lands(grid) != 1)
+                    return 1;
+
+                grid[r][c] = 1;        
+            }
+        }
+
+        return 2;
+    }
+    private void dfs(int[][] grid, int r, int c, Set<String> visited){
+        if(r < 0 || c < 0 || r >= grid.length || c >= grid[r].length || grid[r][c] == 0)
+            return;
+
+        String pos = r + "," + c;
+        if(visited.contains(pos))
+            return;
+
+        visited.add(pos);
+
+        dfs(grid, r+1, c, visited);    
+        dfs(grid, r, c+1, visited);    
+        dfs(grid, r-1, c, visited);    
+        dfs(grid, r, c-1, visited);    
+    }
+    
+    private int count_lands(int[][] grid){
+        Set<String> visited = new HashSet<>();
+        int count = 0;
+
+        for(int r = 0; r < grid.length; r++){
+            for(int c = 0; c < grid[r].length; c++){
+                if(grid[r][c] == 1 && !visited.contains(r + "," + c)){
+                    dfs(grid, r, c, visited);
+                    count += 1;
+                }
+            }
+        }
+
+        return count;
+    }
+}