Added solution

Author: avidLearnerInProgress

maximal_rectangle.cpp

@@ -0,0 +1,26 @@
+class Solution {
+public:
+    int dfs(vector<vector<char>>& matrix, int i, int j){
+        if(i < 0 or j < 0 or i >= matrix.size() or j >= matrix[i].size() or matrix[i][j] == '0')
+            return 0;
+        else{
+            matrix[i][j] = '0';
+            return 1 + dfs(matrix, i-1, j) + dfs(matrix, i+1, j) + dfs(matrix, i, j + 1) + dfs(matrix, i, j - 1);
+        }
+    }
+    
+    int maximalRectangle(vector<vector<char>>& matrix) {
+        if(matrix.size() == 0) return 0;
+        auto curr_area = 0, max_area = INT_MIN;
+        
+        for(auto i = 0; i < matrix.size(); i++){
+            for(auto j = 0; j < matrix[i].size(); j++){
+                if(matrix[i][j] == '1'){
+                    curr_area = dfs(matrix, i, j);
+                    max_area = max(max_area, curr_area);
+                }
+            }
+        }
+        return max_area;
+    }
+};