public class Solution {
public int[] productExceptSelf(int[] nums) {
if (nums == null || nums.length < 1) return nums;
int n = nums.length;
int[] res = new int[n];
res[0] = 1;
for (int i = 1; i < n; i++){
res[i] = res[i - 1] * nums[i - 1];
}
int right = 1;
for(int i = n - 1; i >= 0 ; i--) {
res[i] *= right;
right *= nums[i];
}
return res;
}
}