50146. Merge Link Lists, Again
難度：4.2/51
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53#include <stdio.h>
#include <stdlib.h>
#include "merge.h"
// typedef struct node {
// int data;
// struct node *next;
// }Node;
static int cnt = 0;
Node *merge(Node *list[], int k){
Node* head = (Node*) malloc(sizeof(Node));
Node* prev = head;
cnt = 0;
for(int i = 0; i < k; i++) if(list[i] != NULL) cnt++;
int init_1, init_2, di_1, di_2;
#ifdef ZIGZAG
init_1 = 0, init_2 = k - 1;
di_1 = 1, di_2 = -1;
#endif
#ifdef TOPDOWN
init_1 = 0, init_2 = 0;
di_1 = 1, di_2 = 1;
#endif
#ifdef BOTTOMUP
init_1 = k - 1, init_2 = k - 1;
di_1 = -1, di_2 = -1;
#endif
while(cnt > 0){
for(int i = init_1; i < k && i >= 0; i += di_1){
if(list[i] == NULL) continue;
Node* now = list[i];
list[i] = list[i]->next;
if(list[i] == NULL) cnt--;
prev->next = now;
prev = now;
}
for(int i = init_2; i < k && i >= 0; i += di_2){
if(list[i] == NULL) continue;
Node* now = list[i];
list[i] = list[i]->next;
if(list[i] == NULL) cnt--;
prev->next = now;
prev = now;
}
}
return head->next;
}