链表操作

title: 链表基本操作date: 2020-10-18 22:44:41
tags: C++
categories: 算法

code

#include <iostream>
#include <string>
using namespace std;
#define MAXLEN 40
#define ERROR 0
#define OK 1
#define NOT -1
typedef struct
{
    char ch[MAXLEN]; 
    int len;        
} SString;
//函数：创建链表
void initSString(SString *p,char ch_[MAXLEN])
{
    strcpy(p->ch,ch_);
    p->len = strlen(p->ch);
}
//函数：在指定坐标前插入字符串(在LA和LB段间接上LC段)
int Insert(SString *s, int pos, const SString *t)
{
    int i;
    if (pos < 0 || pos > s->len)  //插入位置不合法
        return ERROR; 
    if (s->len + t->len <= MAXLEN)  //A+B+C <= MAXLEN
    { 
        for (i = s->len + t->len - 1; i >= pos + t->len; i--)
            s->ch[i] = s->ch[i - t->len];
        for (i = 0; i < t->len; i++)
            s->ch[i + pos] = t->ch[i];
        s->len = s->len + t->len;
    }
    else if (pos + t->len <= MAXLEN)  //A+B <= MAXLEN C要截取
    { 
        for (i = MAXLEN - 1; i >= pos + t->len; i--)
            s->ch[i] = s->ch[i - t->len];
        for (i = 0; i < t->len; i++)
            s->ch[i + pos] = t->ch[i];
        s->len = MAXLEN;
    }
    else  //A <= MAXLEN B和C都要截取
    {
        for (i = 0; i < MAXLEN - pos; i++)  
            s->ch[i+pos] = t->ch[i];
    }
    return OK;
}
//函数：从pos下标位置开始，删除l个元素
StrDelete(SString *s, int pos, int l)
{
    int i;
    if (pos < 0 || pos > (s->len - l))
        return ERROR;
    for (i = pos + l; i < s->len; i++)
        s->ch[i - l] = s->ch[i];
    s->len = s->len - l; 
    return OK;
}
//函数：求从主串pos下标开始，返回第一个子串首元素下标，没有返回0
int index_BF(const SString *s,const SString *sub,int pos)
{
    if(pos < 0 || pos > (s->len-1))
        return ERROR;
    int i = pos;int j = 0;
    int lens = strlen(s->ch);
    int lensub = strlen(sub->ch);
    while(i < lens && j < lensub)
    {
        if(s->ch[i] == sub->ch[j]){i++;j++;}
        else {i = i-j+1;j = 0;}
    }
    if(j >= sub->len)
        return i - j;
    else return NOT; //不是子串
}
main()
{
    int t = 0;
    char str[100];
    SString s = {"abcdef",6};
    SString sub = {"labcde",6};
    SString a;
    cout<<"Input: "<<endl;
    cin>>str;
    initSString(&a,str);
    cout<<a.ch<<endl;
    cout<<a.len<<endl;
    return 0;
}