# LeetCode 238. Product of Array Except Self

### Kaitian Xie ・1 min read

```
public class Solution {
public int[] productExceptSelf(int[] nums) {
int len = nums.length;
int[] ans = new int[len];
for (int i = 0, temp = 1; i < len; i++) {
ans[i] = temp;
temp *= nums[i];
}
for (int i = len - 1, temp = 1; i >= 0; i--) {
ans[i] *= temp;
temp *= nums[i];
}
return ans;
}
}
```

After the first for loop, `nums[i]`

is equal to the product of the numbers from `0`

to `i - 1`

. At each iteration of the second for loop, `nums[i]`

is multiplied by the product of the numbers from `i + 1`

to `len - 1`

. Therefore, after the two for loops, `nums[i] = nums[0] * nums[1] * ... * nums[i-1] * ... * nums[i+1] * ... * nums[len-1]`

.

*Time Complexity*: `O(n)`

*Extra Space*: `O(1)`

Classic DEV Post from May 28