Create 200. Number of Islands (#460)

Author: Chayandas07

200. Number of Islands

@@ -0,0 +1,27 @@
+class Solution {
+public:
+    vector<int>dx{0,0,1,-1};
+    vector<int>dy{1,-1,0,0};
+    void solve(int i,int j,int n,int m,vector<vector<char>>& v) {
+        if(i<0 || j<0 || i>=n || j>=m || v[i][j]=='0' || v[i][j]=='2')
+            return;
+        v[i][j]='2';
+        for(int k=0;k<4;k++) {
+            solve(i+dx[k],j+dy[k],n,m,v);
+        }
+    }
+    int numIslands(vector<vector<char>>& v) {
+        int n=v.size();
+        int m=v[0].size();
+        int ans=0;
+        for(int i=0;i<n;i++) {
+            for(int j=0;j<m;j++) {
+                if(v[i][j]=='1') {
+                    solve(i,j,n,m,v);
+                    ans++;
+                }
+            }
+        }
+        return ans;
+    }
+};