2021“MINIEYE杯”中国大学生算法设计超级联赛（8）- 1009（Singing Superstar）

补题链接：​​https://acm.hdu.edu.cn/showproblem.php?pid=7064​​

​​板子题：字符串hash​​

​​code​​

#include<iostream>
#include<algorithm>
#include <cstring>
#include <unordered_map>

using namespace std;

// 2^64,让其自然溢出,相当于对2^64取mod
typedef unsigned long long ULL;

// P(进制数)一般取131/13331
const int N = 100010, P = 131;

int n, m;
char str[N];
ULL h[N], p[N];

// 求[l, r]区间的字符串的hash值
ULL get(int l, int r){

    // 1 ~ (l - 1)(从高位到低位)
    // 1 ~ r (从高位到低位)
    // L ~ R (相当于把h[l - 1]左移动(r - (l - 1))位, 然后用h[r]减去)
    return h[r] - h[l - 1] * p[r - l + 1];
}

void solve(){

    scanf("%s", str + 1);

    n = strlen(str + 1);

    unordered_map<ULL, int> cnt;
    unordered_map<ULL, int> lst;

    p[0] = 1;
    for(int i = 1; i <= n; i++){

        h[i] = h[i - 1] * P + str[i];
        p[i] = p[i - 1] * P;
    }

    scanf("%d", &m);

    char chs[33];
    ULL a[m];

    for (int i = 1; i <= m; ++i) {

        scanf("%s", chs + 1);

        ULL hs = 0;
        for (int i = 1; chs[i]; ++i) {
            hs = hs * P + chs[i];
        }

        a[i] = hs;
        cnt[hs] = 0;
        lst[hs] = 0;
    }

    for (int len = 1; len <= 30; ++len) {
        for (int i = 1; i + len - 1 <= n; ++i) {

            ULL hs = get(i, i + len - 1);
            if(cnt.count(hs) && lst[hs] <= i){

                lst[hs] = i + len;
                cnt[hs]++;
            }
        }
    }

    for (int i = 1; i <= m; ++i) {

        printf("%d\n", cnt[a[i]]);
    }
}

int main(){

    int t;

    scanf("%d", &t);

    while(t--) solve();

    return 0;
}