hdu 1711 kmp

最新推荐文章于 2022-08-16 16:03:58 发布

原创最新推荐文章于 2022-08-16 16:03:58 发布 · 398 阅读

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#C++ #字符串 #kmp

裸题,直接匹配一遍

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#define M 10007
#define N 1000007

using namespace std;

int s[N],p[M];

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

int match ( int s[] , int p[] , int n , int m)
{
    int next[M];
    get_next ( p , next , m );
    int i = 1 , j = 1;
    while ( i <= n )
    {
        if ( !j || s[i] == p[j] ) i++,j++;
        else j = next[j];
        if ( j == m+1 ) return i-m;
    }
    return -1;
}

int t,n,m;

int main ( )
{
    scanf ( "%d" , &t );
    while ( t-- )
    {
        scanf ( "%d%d" , &n , &m );
        for ( int i = 1; i <= n; i++ )
            scanf ( "%d" , &s[i] );
        for ( int i = 1; i <= m; i++ )
            scanf ( "%d" , &p[i] );
        printf ( "%d\n" , match ( s , p , n , m ) );
    }
}