Graph ques and Trie added

Author: cs-cse

.idea/modules.xml

@@ -1,5 +1,6 @@
 import java.util.LinkedList;
 import java.util.Queue;
+import java.util.Stack;
 
 public class AdjListGraph {
 //  Undirected graph implementation using list.
@@ -43,13 +44,32 @@ public void bfs(int s){
         while (!q.isEmpty()){
             int u=q.poll();
             System.out.print(u+" ");
+
             for(int v:adj[u]){
                 if(!visited[v]){
                     visited[v]=true;
                     q.offer(v);
                 }
             }
         }
+        System.out.println();
+    }
+    public void dfs(int s){
+        boolean[]visited=new boolean[V];
+        Stack<Integer>stack=new Stack<>();
+        stack.push(s);
+        while (!stack.isEmpty()){
+            int u=stack.pop();
+            if(!visited[u]){
+                visited[u]=true;
+                System.out.print(u+" ");
+                for (int v:adj[u]){
+                    if (!visited[v]){
+                        stack.push(v);
+                    }
+                }
+            }
+        }
     }
 
     public static void main(String[] args) {
@@ -60,6 +80,7 @@ public static void main(String[] args) {
         g.addEdge(3, 0);
         // 4
         g.bfs(0);
+        g.dfs(0);
 
 
     }

dsa-Graph/src/AdjListGraph.java

@@ -0,0 +1,40 @@
+public class NumberOfIslands {
+
+    public static int numIslands(char[][]grid){
+        int m=grid.length;
+        int n=grid[0].length;
+        boolean[][]visited=new boolean[m][n];
+        int numOfIslands=0;
+        for(int i=0;i<m;i++){
+            for(int j=0;j<n;j++){
+                if(!visited[i][j]&&grid[i][j]=='1'){
+                    dfs(grid,i,j,visited);
+                    numOfIslands++;
+                }
+            }
+        }
+        return numOfIslands;
+    }
+    public static void dfs(char[][] grid, int row, int col, boolean[][] visited){
+        if(row<0||col<0||row> grid.length||col>= grid[0].length|| visited[row][col]||grid[row][col]=='0'   ){
+            return;
+        }
+        visited[row][col]=true;
+        dfs(grid,row,col-1,visited);
+        dfs(grid,row-1,col,visited);
+        dfs(grid,row,col+1,visited);
+        dfs(grid,row+1,col,visited);
+    }
+
+
+    public static void main(String[] args) {
+char [][]a={
+        {1,1,0,0},
+        {1,0,0,0},
+        {0,0,1,0},
+        {0,0,0,1}
+};
+int c=numIslands(a);
+        System.out.println(c);
+    }
+}

dsa-Graph/src/NumberOfIslands.java

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>