#include <iostream>
#include <cstring>
using namespace std;
const int N = 1e6 + 10;
char s[N], p[N];
int ne[N];
int stk[N], f[N], top;
int main () {
cin >> s + 1 >> p + 1;
int n = strlen (s + 1), m = strlen (p + 1);
for (int i = 2, j = 0; i <= m; i ++) {
while (j && p[j + 1] != p[i]) j = ne[j];
if (p[j + 1] == p[i]) j ++;
ne[i] = j;
}
for (int i = 1, j = 0; i <= n; i ++) {
while (j && s[i] != p[j + 1]) j = ne[j];
if (s[i] == p[j + 1]) j ++;
f[i] = j;
stk[++top] = i;
if (j == m) {
top -= m;
j = f[stk[top]];
}
}
for (int i = 1; i <= top; i ++)
cout << s[stk[i]];
return 0;
}
如何實作kmp删除字串?用棧記錄每一個模闆串的下标,然後用一個數組記錄f[i] = j,記錄一個下标對應的比對串比對到的位置。如果j=m表示比對成功,然後在棧中删除對應數量的下标,并把j重新定位到新的棧頂元素對應的比對串比對到的位置。