Given an array of positive integers. All numbers occur even number of * times except one number which occurs odd number of times. Find the number * in O(n) time & constant space.

NumberAppearingOddNumberOfTimesInArray.java

/**
 * 
 * Given an array of positive integers. All numbers occur even number of 
 * times except one number which occurs odd number of times. Find the number 
 * in O(n) time & constant space.

Example:
I/P = [1, 2, 3, 2, 3, 1, 3]
O/P = 3


 * @author paveynganpi
 *
 */

public class NumberAppearingOddNumberOfTimesInArray {
	
	public static void main(String[]args){
		System.out.println(1^2);
		System.out.println( "i    res    arr");
		int arr[] = {1, 2, 3, 2, 3, 1, 3};
		int res = 0;
		for(int i =0;i<arr.length;i++){
			res = res^arr[i];
			System.out.println(i+ "   " + res + "   " + arr[i]);
		}
		
	    System.out.println(res);
		
	}

}