Linklist merge sort (Microsoft and other interview one hundred questions-linked list sorting) Code

Because you writeProgramThis problem has been fixed, so I wrote a handwriting + machine test. Although I was very careful, I still wrote a Bug During the machine test, therefore, sending this post makes your memory persistent.

The problem is as follows:

1. Write a method for sorting linked listsAlgorithm. Why do you choose to use this method?

CodeAs follows:

# Include <stdio. h> # include <stdlib. h> struct linknode {int data; linknode * pnext; linknode (INT _ DATA) {DATA = _ data; pnext = NULL ;}}; linknode * mergelink (linknode * pleftlink, linknode * prightlink) {linknode * pH = NULL, * P = NULL; while (pleftlink & prightlink) {If (pleftlink-> data <prightlink-> data) {If (pH = NULL) {pH = P = pleftlink; pleftlink = pleftlink-> pnext;} else {P-> pnext = pleftlink; P = p-> pnext; pleftl Ink = pleftlink-> pnext;} else {If (pH = NULL) {pH = P = prightlink; prightlink = prightlink-> pnext ;} else {P-> pnext = prightlink; P = p-> pnext; prightlink = prightlink-> pnext ;}} p-> pnext = (pleftlink = NULL )? Prightlink: pleftlink; return pH;} linknode * mergesort (linknode * phead, int Len) {If (LEN = 1) {phead-> pnext = NULL; return phead ;} // when The bug is written here. I first run mergesort (phead, Len/2), and then use the phead to request prightstart. Linknode * prightstart = phead; For (INT I = 0; I <Len/2; I ++) {prightstart = prightstart-> pnext;} linknode * plefthalf = mergesort (phead, len/2); linknode * prighthalf = mergesort (prightstart, len-len/2); linknode * pmergedlink = mergelink (plefthalf, prighthalf); Return pmergedlink ;} void printall (linknode * phead) {int I = 1; while (phead) {printf ("% d", phead-> data); phead = phead-> pnext; if (I ++ % 20 = 0) {printf ("\ n") ;}} int main () {linknode * phead = NULL; linknode * pcurrent = NULL; int flags [300] = {0}; For (INT I = 0; I <10;) {int num = rand () % 300; If (flags [num]) {continue;} else {flags [I] = 1; I ++; linknode * pnewnode = new linknode (Num); If (phead = NULL) {phead = pcurrent = pnewnode;} else {pcurrent-> pnext = pnewnode; pcurrent = pcurrent-> pnext ;}} printall (phead ); printf ("\ n"); phead = mergesort (phead, 10); printall (phead); Return 0 ;}