呢個solution
Time complexity 應該係O(n*k* log(n*k))
n係number of node,
K 係number of int in a node
log(n*k) 係因為到conquer個part 係有log(n*k)層
每層都除2直到變1條array...
網上搵到個solution 係o(n*k* log k)
https://www.google.com.hk/amp/s/www.geeksforgeeks.org/merge-k-sorted-arrays/amp/
有錯屌勿屌