Class Solution

FindtheDuplicateNumber.java:1–17

class Solution 
{
    public int findDuplicate(int[] nums) 
    {
        int index=0;
        for(int i=0;i<nums.length;i++)
        {
            index=Math.abs(nums[i])-1;
            if(nums[index]<0)
            {
                return Math.abs(nums[i]);
            }
            nums[index]=-nums[index];
        }
        return -1;
    }
}