KMP模板

Posted 2020-08-31 LuZhiyuan

详解：

http://www.cppblog.com/oosky/archive/2006/07/06/9486.html

http://www.matrix67.com/blog/archives/115

http://blog.csdn.net/v_july_v/article/details/7041827

http://kb.cnblogs.com/page/176818/

白书上的代码：

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn=1000006;
const int maxm=10004;
char P[maxn],T[maxn];//P待匹配模板串
int f[maxm],f2[maxm];
void getfail(char* P,int* f){
    int m=strlen(P);
    f[0]=0;f[1]=0;
    f2[0]=0;f2[1]=0;
    for(int i=1;i<m;i++){
        int j=f2[i];
        while(j&&P[i]!=P[j]) j=f2[j];
        f2[i+1]=f[i+1]=(P[i]==P[j]?j+1:0);
        if(f[i+1]==j+1&&P[i+1]==P[j+1]) f[i+1]=f[j+1];
    }
}
int find(char* T,char* P,int* f){
    int n=strlen(T),m=strlen(P);
    getfail(P,f);
    int j=0;
    for(int i=0;i<n;i++){
        while(j&&P[j]!=T[i]) j=f[j];
        if(P[j]==T[i]) j++;
        if(j==m) return i-m+1;//编号从0开始
    }
    return -1;
}
int main()
{
    return 0;
}