手工执行算法k-merge，追踪败者树变化过程。假设初始归并

手工执行算法k-merge，追踪败者树变化过程。假设初始归并段为：
(10, 15, 16, 20, 31, 39, +∞);
(9, 18, 20, 25, 36,48, +∞);
(20, 22, 40, 50, 67, 79, +∞);
(6, 15, 25, 34, 42, 46, +∞);
(12, 37, 48, 55, +∞);
(84, 95, +∞)