Merge pull request #23 from Shrikant991/leetcodeSolutions

Added IslandPerimeter.cpp

Author: Soumalya1857

Sites/Leetcode.md

@@ -35,3 +35,4 @@
 * [Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/) , [Solution](../Solutions/FindMedianFromDataStream.cpp)
 * [4 Sum](https://leetcode.com/problems/4sum/) , [Solution](../Solutions/4Sum.cpp)
 * [2 Keys Keyboard](https://leetcode.com/problems/2-keys-keyboard/) , [Solution](../Solutions/2KeysKeyboard.cpp)
+* [Island Perimeter] (https://leetcode.com/problems/island-perimeter/) ,[Solution] (../Solutions/IslandPerimeter.cpp)

Solutions/IslandPerimeter.cpp

@@ -0,0 +1,39 @@
+/*
+The solution is basically based on DFS of a graph.
+The Borders in the graph are shown as 1s so that they may add upto the perimeter.
+*/
+class Solution {
+public:
+int DFS(vector<vector<int>>& grid,int x, int y,vector<vector<bool>>&visited){
+
+if(x<0||y<0||x>=grid.size()||y>=grid[0].size()||!grid[x][y]) // Border Condition Checking
+return 1;
+if(visited[x][y]) // Already Visited Graph
+return 0;
+
+visited[x][y] = true;
+
+int a = DFS(grid,x+1,y,visited); // DFS Calls for Adjacent cells
+a +=DFS(grid,x-1,y,visited);
+a +=DFS(grid,x,y+1,visited);
+a +=DFS(grid,x,y-1,visited);
+
+return a;
+}
+int islandPerimeter(vector<vector<int>>& grid) {
+
+vector<vector<bool>>visited(grid.size(),vector<bool>(grid[0].size(),false));
+
+for(int i = 0;i<grid.size();i++)
+{
+for(int j = 0;j<grid[i].size();j++)
+{
+if(grid[i][j]) // Calls for all the connected Components
+{
+return DFS(grid,i,j,visited);
+}
+}
+}
+return 0;
+}
+};