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最新推荐文章于 2022-09-23 12:44:21 发布

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最新推荐文章于 2022-09-23 12:44:21 发布

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分类专栏： ACM_HDU ACM_数据结构

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题意:

给定一个字符串，求长度为m * l的子串的数目，要求该子串由m段长度为l的字符串组成，且m段互不相同

#include 
#include 
#include 
#include 
using namespace std;

map  mymap;
const unsigned int seed = 31;
unsigned int base[100010], hash[100010];
char s[100010];
int m, l;

int main() {
    base[0] = 1;
    for (int i = 1; i <= 100000; i ++) {
        base[i] = base[i - 1] * seed;
    }
    while (scanf("%d%d", &m, &l) == 2) {
        scanf("%s", s + 1);
        int len = strlen(s + 1);
        hash[len + 1] = 1;
        for (int i = len; i >= 1; i --) {
            hash[i] = hash[i + 1] * seed + s[i] - 'a';
        }
        int ans = 0;
        for (int i = 1; i + m * l - 1 <= len && i <= l; i ++) {
            mymap.clear();
            for (int j = i; j <= i + (m - 1) * l; j += l) {
                unsigned int tmp = hash[j] - hash[j + l] * base[l];
                mymap[tmp] ++;
            }
            if (mymap.size() == m) {
                ans ++;
            }
            for (int j = i + m * l; j + l - 1 <= len; j += l) {
                unsigned int tmp = hash[j - m * l] - hash[j - m * l + l] * base[l];
                mymap[tmp] --;
                if (mymap[tmp] == 0) mymap.erase(tmp);
                tmp = hash[j] - hash[j + l] * base[l];
                mymap[tmp] ++;
                if (mymap.size() == m) {
                    ans ++;
                }
            }
        }
        printf("%d\n", ans);
    }
    return 0;
}