leetcode questions: two sum

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    // my answer
    var result = [];
    var length = nums.length;
    if (length > 0) {
        for (var i = 0; i < length; i++) {
            var tmp = target - nums[i];
            var tmpIndex = nums.lastIndexOf(tmp);
            if (tmpIndex > 0) {
                result = [i, tmpIndex];
                break;
            }
        }
    }
    return result;
};