Time: 23 ms (92.62%), Space: 12.5 MB (67.49%) - LeetHub

0200-number-of-islands/0200-number-of-islands.cpp

@@ -0,0 +1,37 @@
+class Solution {
+public:
+    int n;
+    int m;
+    void solve(int i,int j,vector<vector<char>> &grid)
+    {
+        if(i<0 || j>=m || i>=n || j<0 || grid[i][j]=='0' || grid[i][j]=='-')return;
+
+        grid[i][j]='-';
+        solve(i-1,j,grid);
+        solve(i,j-1,grid);
+        solve(i+1,j,grid);
+        solve(i,j+1,grid);
+
+    }
+    int numIslands(vector<vector<char>>& grid) {
+        n=grid.size();
+        m=grid[0].size();
+        if(grid.size()==0)
+        return 0;
+        int ans=0;
+
+        for(int i=0;i<n;i++)
+        {
+            for(int j=0;j<m;j++)
+            {
+                if(grid[i][j]=='1')
+                {
+                    solve(i,j,grid);
+                    ans++;
+                }
+            }
+        }
+        return ans;
+
+    }
+};