题目
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.)
class Solution {
public int[] productExceptSelf(int[] nums) {
int[] ans = new int[nums.length];
if(nums.length == 0) return ans;
int curr_product = 1;
ans[0] = 1;
for(int i = 1; i < nums.length; i++) {
ans[i] = ans[i-1] * nums[i - 1];
}
for(int j = nums.length - 1; j >= 0; j--) {
ans[j] = curr_product * ans[j];
curr_product = curr_product * nums[j];
}
return ans;
}
}
