题意: Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. (Hard) 分析: 方法1: 利用做过的merge 2 sorted list,将头两个归并,结果再与下一个归并,以此类推,归并完所有. 时间复杂度分析是个小问题, merge 2 sorted list的复杂度是O(n),本以为结果就是O(n * k). 但是仔细考虑,随着归并不断进行,其…