hdu 2203 kmp 模板题

最新推荐文章于 2020-08-28 18:52:19 发布

黎辰

最新推荐文章于 2020-08-28 18:52:19 发布

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文章标签： C++ 字符串 kmp

本文链接：https://blog.youkuaiyun.com/qq_24451605/article/details/44173747

本文详细介绍了使用C++实现的字符串匹配算法，包括获取前缀数组和匹配字符串的功能。

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#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#define MAX 100007

using namespace std;

char s1[MAX<<1],s2[MAX];

void get_next ( char p[] , int next[] )
{
    int len = strlen ( p );
    int i = 0 , k = -1;
    next[0] = -1;
    while ( i != len )
    {
        if ( k == -1 || p[i] == p[k] ) 
            i++,k++,next[i] = k;
        else k = next[k];
    }
}

bool match ( char s[] , char p[] )
{
    int next[MAX];
    get_next ( p , next );
    int i = 0 , j = 0;
    int len1 = strlen ( s );
    int len2 = strlen ( p );
    while ( i < len1 )
    {
        if ( j == -1 || s[i] == p[j] ) i++,j++;
        else j = next[j];
        if ( j == len2 ) return true;
    }
    return false;
}

int main ( )
{
    while ( ~scanf ( "%s" , s1 ) )
    {
        scanf ( "%s" , s2 );
        int len = strlen ( s1 );
        for ( int i = len ; i < 2*len ; i++ )
            s1[i] = s1[i-len];
        s1[2*len] = 0;
        if ( strlen(s1) < strlen(s2) || !match ( s1 , s2 ) )
            puts ( "no" );
        else puts ( "yes" );
    }
}