Product of Array Except Self

1package pkg5leetcode.official75;2 3/*4 * Product of Array Except Self | LC 2385 * APPROACH: Prefix then suffix pass without division.6 * COMPLEXITY: Time O(n), Space O(1) extra7 */8public class official75_LC238ProductOfArrayExceptSelf {9    static int[] productExceptSelf(int[] nums) {10        int n = nums.length;11        int[] res = new int[n];12        res[0] = 1;13        for (int i = 1; i < n; i++) res[i] = res[i - 1] * nums[i - 1];14        int suffix = 1;15        for (int i = n - 1; i >= 0; i--) {16            res[i] *= suffix;17            suffix *= nums[i];18        }19        return res;20    }21 22    public static void main(String[] args) {23        check(java.util.Arrays.equals(productExceptSelf(new int[]{1,2,3,4}), new int[]{24,12,8,6}), "case1");24        check(java.util.Arrays.equals(productExceptSelf(new int[]{-1,1,0,-3,3}), new int[]{0,0,9,0,0}), "case2");25        System.out.println("all tests passed");26    }27 28    static void check(boolean cond, String name) {29        if (!cond) throw new AssertionError("FAILED: " + name);30        System.out.println("  PASS " + name);31    }32}