题解 | #单链表的排序#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param head ListNode类 the head node
 * @return ListNode类
 */
#include <stdbool.h>
#include <stdlib.h>
struct ListNode* sortInList(struct ListNode* head ) {
    // write code here
    struct ListNode* headlist[19];
    struct ListNode* endlist[19];
    struct ListNode* rtn = malloc(sizeof(struct ListNode));
    struct ListNode* tmp = head;
    bool flag = true;
    rtn->next = NULL;
    rtn->val = 0;
    int i = 0;
    for(i = 0;i<19;i++){
        headlist[i] = NULL;
        endlist[i] = NULL;
    }

    int count = 1;
    while(flag){
        flag = false;
        rtn->next = NULL;
        while(tmp!=NULL){  
            int index = tmp->val / count;
            if(index!=0){
                flag = true;
            }
            index = index%10;
            if(headlist[index+9] == NULL){
                headlist[index+9] = tmp;
            }else{
                endlist[index+9]->next = tmp;
            }
            endlist[index+9] = tmp;
            tmp = tmp->next;
            endlist[index+9]->next = NULL;
        }

        int last = 0;
        for(i = 0;i<19;i++){
            if(headlist[i]!=NULL){
                if(rtn->next == NULL){
                    rtn->next = headlist[i];
                }else{
                    endlist[last]->next = headlist[i];
                    endlist[last] = NULL; 
                }
                last = i;
                headlist[i] = NULL;
            }
        }
        endlist[last] = NULL;
        tmp = rtn->next;
        count = count*10;
    }
    return rtn->next;
}