洛谷-p5410-扩展KMP模板

链接:

https://www.luogu.org/problem/P5410#submit

题意:

有两个字符串aa,bb,要求输出bb与aa的每一个后缀的最长公共前缀

思路:

扩展kmp模板, 上一个大佬的详解链接
https://segmentfault.com/a/1190000008663857

代码:

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5+10;

char a[MAXN], b[MAXN];
int Next[MAXN], Exten[MAXN];

void GetNext(char *t)
{
    int p = 0, a = 0;
    int len = strlen(t);
    Next[0] = len;
    for (int i = 1;i < len;i++)
    {
        if (i >= p || i+Next[i-a] >= p)
        {
            if (i >= p)
                p = i;
            while (p < len && t[p] == t[p-i])
                p++;
            Next[i] = p-i;
            a = i;
        }
        else
            Next[i] = Next[i-a];
    }
}

void ExKmp(char *s, char *t)
{
    int a = 0, p = 0;
    int len = strlen(s);
    GetNext(t);
    for (int i = 0;i < len;i++)
    {
        if (i >= p || i+Next[i-a] >= p)
        {
            if (i >= p)
                p = i;
            while (p < len && s[p] == t[p-i])
                p++;
            Exten[i] = p-i;
            a = i;
        }
        else
            Exten[i] = Next[i-a];
    }
}

int main()
{
    scanf("%s %s", a, b);
    ExKmp(a, b);
    for (int i = 0;i < strlen(b);i++)
        printf("%d ", Next[i]);
    puts("");
    for (int i = 0;i < strlen(a);i++)
        printf("%d ", Exten[i]);
    puts("");

    return 0;
}