算法，合并两个有序数组，使用双指针算法

 private static Long[] sortArray(Long[] arr1, Long[] arr2) {
        Long[] result = new Long[arr1.length + arr2.length];
        int p1 = 0;
        int p2 = 0;
        int curr = 0;
        while (p1 < arr1.length && p2 < arr2.length) {
            if (arr1[p1] < arr2[p2]) {
                result[curr] = arr1[p1];
                p1++;
            } else {
                result[curr] = arr2[p2];
                p2++;
            }
            curr++;
        }

        if (p1 < arr1.length) {
            System.arraycopy(arr1, p1, result, curr, arr1.length - p1);
        } else if (p2 < arr2.length) {
            System.arraycopy(arr2, p2, result, curr, arr2.length - p2);
        }
        return result;

    }