​https://ac.nowcoder.com/acm/contest/955/F​

#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;
}
如何实现kmp删除字串?用栈记录每一个模板串的下标,然后用一个数组记录f[i] = j,记录一个下标对应的匹配串匹配到的位置。如果j=m表示匹配成功,然后在栈中删除对应数量的下标,并把j重新定位到新的栈顶元素对应的匹配串匹配到的位置。