censoring--kmp匹配删减子字符串

传送门

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 10;
char a[maxn], b[maxn], st[maxn];
int nex[maxn], p[maxn];
 
void getNext() {
    int len = strlen(b), i = 0, j = -1;
    nex[0] = -1;
    for (int i = 1; i < len; i++) {
        while (j != -1 && b[i] != b[j + 1]) j = nex[j];
        if (b[i] == b[j + 1])
            j++;
        nex[i] = j;
    }
}
 
void KMP() {
    int n = strlen(a), m = strlen(b);
    getNext();
    int top = 0;
    for (int i = 0; i < n; i++) {
        int j = p[top];
        st[++top] = a[i];
        while (j != -1 && b[j + 1] != st[top]) j = nex[j];
        if (b[j + 1] == st[top])
            j++;
        p[top] = j;
        if (p[top] + 1 == m)
            top -= m;
    }
    st[top + 1] = 0;
    puts(st + 1);
}
 
int main() {
    scanf("%s%s", a, b);
    KMP();
    return 0;
}