二叉树查找、匹配字符串、快速排序

题记：一个面试题目，让我羞耻的面试题目，40分钟真得没有写出来，C语言的指针真是麻烦到家

题目大意，在一个二叉树中，找出匹配子串的节点，并使用快速排序找出第n大的节点。排序规则：字串出现次数，字符数，ascii排序。

#include <stdio.h>#include <stdlib.h>#include <string.h>#define SIZE 100struct TreeNode{    char *str;    struct TreeNode *left, *right;};struct help{    int num;    struct TreeNode *node;};struct help pall[SIZE]={};;int inde =0;int com(struct help *p1,struct help *p2){    if(p1->num < p2->num){        return 1;    }    if(p1->num == p2->num){        if(strlen(p1->node->str) <strlen(p2->node->str))        {            return 1;        }        if(strlen(p1->node->str) == strlen(p2->node->str)){            if(strcmp(p1->node->str,p2->node->str) <0){                return 1;            }        }    }    return 0;}struct TreeNode * qsort1(struct help *p, int n ,int k){    struct help h = p[0];    int i=0,j=n-1,index=0;    if(n<k) {         return;    }    while(i<j){        while(i<j && !com(&h,p+j)) j--;        *(p+i)=*(p+j);        while(i<j && com(&h,p+i)) i++;        *(p+j)=*(p+i);    }    *(p+i) = h;    if(i ==(k-1)){        /*int j=0;        for( j=0;j<inde; j++){            printf("sorted %s\n",pall[j].node->str);        }*/        return (p+i)->node;    }else if(i >(k-1)){        /*int j=0;for( j=0;j<inde; j++){            printf("sorted %s\n",pall[j].node->str);        }        printf("--------- pre");*/        return qsort1(p,i,k);    }else{        /*int j=0;for( j=0;j<inde; j++){            printf("sorted %s\n",pall[j].node->str);        }        printf("--------- back");*/        return qsort1(p+i+1,n-i-1,k-i-1);    }}void inorder(struct TreeNode *node, char *substr){    int *next = (int *)malloc(sizeof(int)*(strlen(substr)+1));    if(node == NULL){        return ;    }    inorder(node->left,substr);    int num =findSubNum(node->str,substr,next);    if(num>0){struct help h = {num,node};    pall[inde++] = h;}    //printf("%s %d\n",node->str,num);    inorder(node->right,substr);}void getnext(char *str, int next[]){    next[0] = next[1] = 0;    int length = strlen(str);    int i =0,j=0 ;    for( i = 1; i < length ; i++){        while(j>0&&(*(str+i)) != (*(str+j)))              j = next[j];        if((*(str+i)) == (*(str+j))) j++;        next[i+1] = j;    }}int findSubNum(char *str, char *substr,int next[]){    getnext(substr,next);    int length = strlen(substr);    int i=0,j=0,num=0;    for(i = 0; i< strlen(str); i++)    {        while(j>0&&((*(str+i))!=(*(substr+j))))            j=next[j];        if((*(str+i))==(*(substr+j)) ) j++;        if(j == length){            num++;            j = next[j];        }    }    return num;}struct TreeNode *findNode(struct TreeNode *node, char *substr,int n){    inorder(node,substr);    /*printf("find node num %d\n",inde);    int i=0;    for( i=0;i<inde; i++){        printf("%s\n",pall[i].node->str);    }*/    qsort1(pall,inde,n);}int main(){    struct TreeNode *root = (struct TreeNode*)malloc(sizeof(struct TreeNode)*1);    struct TreeNode *left = (struct TreeNode*)malloc(sizeof(struct TreeNode)*1);    struct TreeNode *right = (struct TreeNode*)malloc(sizeof(struct TreeNode)*1);     struct TreeNode *leftright = (struct TreeNode*)malloc(sizeof(struct TreeNode)*1);    root->left=left;    root->right =right;    left->left=NULL;    left->right=NULL;    right->left=NULL;    right->right=NULL;    left->right = leftright;    left->left = NULL;    leftright->right =NULL;    leftright->left =NULL;    leftright->str="abedf";    root->str="abced";    left->str="cbcab";    right->str="babefbaad";    char *substr = "ab";    /*struct help p1 = {2,root};    struct help p2 = {2,left};    struct help p3 = {3,right};    //printf("%d",com(&p1,&p2));    p[0]=p1;p[1]=p2;p[2]=p3;*/    printf("%s",findNode(root,substr,4)->str);    //printf("%s",s1.str);    return 0;   //inorder(root,substr);}