package com.interview.graph;
/**
http://www.geeksforgeeks.org/find-number-of-islands/
*/
public class NumberOfIsland {
public int numberOfIsland(int[][] graph){
boolean[][] visited = new boolean[graph.length][graph.length];
int count = 0;
for(int i=0; i < graph.length ; i ++){
for(int j =0 ; j < graph[i].length ; j++){
if(visited[i][j] == false && graph[i][j] == 1) {
count++;
DFS(graph,visited,i,j);
}
}
}
return count;
}
private void DFS(int[][] graph, boolean[][] visited,int i,int j){
if(i <0 || j < 0 || i == graph.length || j == graph[i].length)
{
return;
}
visited[i][j] = true;
if(graph[i][j] == 0){
return;
}
DFS(graph,visited,i,j+1);
DFS(graph,visited,i+1,j);
DFS(graph,visited,i+1,j+1);
DFS(graph,visited,i-1, j+1);
}
public static void main(String args[]){
int matrix[][] = {{1,1,0,1,0},
{1,0,0,1,1},
{0,0,0,0,0},
{1,0,1,0,1},
{1,0,0,0,0}
};
NumberOfIsland island = new NumberOfIsland();
int count = island.numberOfIsland(matrix);
System.out.println(count);
}
}