P3375 【模板】KMP字符串匹配

KMP

https://blog.csdn.net/v_july_v/article/details/7041827
P3375 【模板】KMP字符串匹配

#include <bits/stdc++.h>

using namespace std;
const int maxn = 1e6 + 10;
char s1[maxn], s2[maxn];
int l1, l2;
int nxt[maxn], f[maxn];

void work() {
    for (int i = 2, j = 0; i <= l2; i++) {
        while (j > 0 && s2[i] != s2[j + 1])
            j = nxt[j];
        if (s2[i] == s2[j + 1]) j++;
        nxt[i] = j;
    }
}

void kmp() {
    for (int i = 1, j = 0; i <= l1; i++) {
        while (j > 0 && (j == l2 || s1[i] != s2[j + 1]))
            j = nxt[j];
        if (s1[i] == s2[j + 1]) j++;
        f[i] = j;
        if (f[i] == l2) //s2在s1中的某一次出现
            printf("%d
", i - l2 + 1);
    }
}

int main() {
    //freopen("in","r",stdin);
    scanf("%s", s1 + 1);
    scanf("%s", s2 + 1);
    l1 = strlen(s1 + 1);
    l2 = strlen(s2 + 1);
    work();
    kmp();
    for (int i = 1; i <= l2; i++)
        printf("%d ", nxt[i]);
    return 0;
}