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.)

Similar: 152. Maximum Product Subarray

42. Trapping Rain Water

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

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

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

return output;
}
}