238. Product of Array Except Self

Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].

Solve it without division and in O(n).

For example, given [1,2,3,4], return [24,12,8,6].

Follow up:
Could you solve it with constant space complexity? (Note: The output array does not count as extra space for the purpose of space complexity analysis.)

public class Solution {
  public int[] productExceptSelf(int[] nums) {
    int[] output = new int[nums.length];

    //Multiply left product
    int product = 1;
    for (int i = 0; i < nums.length; i++) {
      output[i] = product;
      product *= nums[i];
    }

    //Multiply right product
    product = 1;
    for (int i = nums.length - 1; i >= 0; i--) {
      output[i] *= product;
      product *= nums[i];
    }
    return output;
  }
}

posted on 2015-07-31 07:14  shini  阅读(109)  评论(0编辑  收藏  举报

导航