New Problem Solution - "Max Area of Island"

README.md

@@ -45,6 +45,7 @@ LeetCode
 |717|[1-bit and 2-bit Characters](https://leetcode.com/problems/1-bit-and-2-bit-characters/) | [Python](./algorithms/python/1-bitAnd2-bitCharacters/isOneBitCharacter.py)|Easy|
 |714|[Best Time to Buy and Sell Stock with Transaction Fee](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-transaction-fee) | [C++](./algorithms/cpp/bestTimeToBuyAndSellStock/BestTimeToBuyAndSellStockWithTransactionFee.cpp)|Medium|
 |712|[Minimum ASCII Delete Sum for Two Strings](https://leetcode.com/problems/minimum-ascii-delete-sum-for-two-strings/) | [C++](./algorithms/cpp/minimumASCIIDeleteSumForTwoStrings/MinimumAsciiDeleteSumForTwoStrings.cpp)|Medium|
+|695|[Max Area of Island](https://leetcode.com/problems/max-area-of-island/) | [C++](./algorithms/cpp/maxAreaOfIsland/MaxAreaOfIsland.cpp)|Medium|
 |687|[Longest Univalue Path](https://leetcode.com/problems/longest-univalue-path/) | [Python](./algorithms/python/LongestUnivaluePath/longestUnivaluePath.py)|Easy|
 |684|[Redundant Connection](https://leetcode.com/problems/redundant-connection/) | [Python](./algorithms/python/RedundantConnection/findRedundantConnection.py)|Medium|
 |674|[Longest Continuous Increasing Subsequence](https://leetcode.com/problems/longest-continuous-increasing-subsequence/) | [Python](./algorithms/python/LongestContinuousIncreasingSubsequence/findLengthOfLCIS.py)|Easy|

algorithms/cpp/maxAreaOfIsland/MaxAreaOfIsland.cpp

@@ -0,0 +1,63 @@
+// Source : https://leetcode.com/problems/max-area-of-island/
+// Author : Hao Chen
+// Date   : 2019-03-26
+
+/***************************************************************************************************** 
+ *
+ * Given a non-empty 2D array grid of 0's and 1's, an island is a group of 1's (representing land) 
+ * connected 4-directionally (horizontal or vertical.) You may assume all four edges of the grid are 
+ * surrounded by water.
+ * 
+ * Find the maximum area of an island in the given 2D array. (If there is no island, the maximum area 
+ * is 0.)
+ * 
+ * Example 1:
+ * 
+ * [[0,0,1,0,0,0,0,1,0,0,0,0,0],
+ *  [0,0,0,0,0,0,0,1,1,1,0,0,0],
+ *  [0,1,1,0,1,0,0,0,0,0,0,0,0],
+ *  [0,1,0,0,1,1,0,0,1,0,1,0,0],
+ *  [0,1,0,0,1,1,0,0,1,1,1,0,0],
+ *  [0,0,0,0,0,0,0,0,0,0,1,0,0],
+ *  [0,0,0,0,0,0,0,1,1,1,0,0,0],
+ *  [0,0,0,0,0,0,0,1,1,0,0,0,0]]
+ * 
+ * Given the above grid, return 6. Note the answer is not 11, because the island must be connected 
+ * 4-directionally.
+ * 
+ * Example 2:
+ * 
+ * [[0,0,0,0,0,0,0,0]]
+ * Given the above grid, return 0.
+ * 
+ * Note: The length of each dimension in the given grid does not exceed 50.
+ ******************************************************************************************************/
+
+class Solution {
+public:
+    int maxAreaOfIsland(vector<vector<int>>& grid) {
+        int maxArea = 0;
+        for (int i=0; i<grid.size(); i++) {
+            for(int j=0; j<grid[0].size(); j++) {
+                if ( grid[i][j] == 1 ) {
+                    int area = 0;
+                    maxAreaOfIsland_DFS(grid, i, j, area);
+                    maxArea = max( maxArea, area );
+                }
+            }
+        }
+        return maxArea;
+    }
+
+    void maxAreaOfIsland_DFS( vector<vector<int>>& grid, int i, int j, int& area ) {
+        if (i<0 || j<0 || i>=grid.size() || j>=grid[0].size() || grid[i][j] != 1 ) return;
+
+        area++;
+        grid[i][j] = -1;
+
+        maxAreaOfIsland_DFS(grid, i-1, j, area);
+        maxAreaOfIsland_DFS(grid, i+1, j, area);
+        maxAreaOfIsland_DFS(grid, i, j-1, area);
+        maxAreaOfIsland_DFS(grid, i, j+1, area);
+    }
+};