238. 除自身以外数组的乘积

执行用时：160 ms, 在所有 Swift 提交中击败了100.00%的用户
内存消耗：19.2 MB, 在所有 Swift 提交中击败了100.00%的用户

class Solution {
    func productExceptSelf(_ nums: [Int]) -> [Int] {
        let n = nums.count
        var res = [Int]()
        var L = [Int].init(repeating: 1, count: n)
        var R = [Int].init(repeating: 1, count: n)
        for i in 1 ..< n {
            L[i] = L[i-1] * nums[i-1]
        }
        for j in (0 ..< n-1).reversed() {
            R[j] = R[j+1] * nums[j+1]
        }
        for i in 0 ..< n {
            res.append(L[i] * R[i])
        }
        return res
    }
}

Java

class Solution {
    public int[] productExceptSelf(int[] nums) {
        int n = nums.length;
        int[] L = new int[n];
        int[] R = new int[n];
        int[] res = new int[n];
        L[0] = 1;
        for (int i = 1; i < n; i++) {
            L[i] = L[i-1] * nums[i-1];
        }
        R[n-1] = 1;
        for (int i = n-2; i >= 0; i--) {
            R[i] = R[i+1] * nums[i+1];
        }
        for (int i = 0; i < n; i++) {
            res[i] = L[i] * R[i];
        }
        return res;
    }
}