序列自动机

模板

查找主串中的子序列

#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 100;
int nxt[maxn][26];

char s[maxn], t[maxn];

int main() {
    scanf("%s", s + 1);
    int len = strlen(s + 1);
    for (int i = len; i >= 1; i--) {
        for (int j = 0; j < 26; j++) {
            nxt[i - 1][j] = nxt[i][j];
        }
        nxt[i - 1][s[i] - 'a'] = i;
    }

    int q;
    scanf("%d", &q);
    while(q--) {
        scanf("%s", t);
        int len1 = strlen(t);
        int f = 0;
        for (int i = 0, u = 0; i < len1; i++) {
            int v = t[i] - 'a';
            u = nxt[u][v];
            if(u==0) {
                f = 1;
                break;
            }
        }
        if(f) {
            printf("NO\n");
        }
        else
            printf("YES\n");
    }
}