解決
文字列ハッシュ
コード
/*Siberian Squirrel*/
/*Cute JinFish*/
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const double PI = acos(-1), eps = 1e-8;
/*const int MOD = 998244353, r = 119, k = 23, g = 3;
const int MOD = 1004535809, r = 479, k = 21, g = 3;*/
const int INF = 0x3f3f3f3f, MOD = 1e9 + 7;
const int M = 3e2 + 10, N = 1e5 + 10;
int sgn(double x) {
if(fabs(x) < eps) return 0;
return x < 0? -1: 1;
}
//inline int rnd(){static int seed=2333;return seed=(((seed*666666ll+20050818)%998244353)^1000000007)%1004535809;}
//double Rand() {return (double)rand() / RAND_MAX;}
ll n, m, l;
string s;
ull Hash[N], bin[N], base = 13331;
map<ull, int> mp;
ll quick_pow(ll ans, ll p, ll res = 1) {
for(; p; p >>= 1, ans = ans * ans % MOD)
if(p & 1) res = res * ans % MOD;
return res % MOD;
}
void init() {
bin[0] = 1;
for(int i = 1; i < N; ++ i) {
bin[i] = bin[i - 1] * base;
}
}
ull get_sub(int l, int r) {
return Hash[r] - Hash[l - 1] * bin[r - l + 1];
}
void solve(ll res = 0, ull temp = 0) {
for(int i = 1; i <= l && i + m * l - 1 <= n; ++ i) {
mp.clear();
for(int j = i; j <= i + m * l - 1; j += l) {
mp[get_sub(j, j + l - 1)] ++;
}
if(mp.size() == m) res ++;
for(int j = i + m * l; j + l - 1 <= n; j += l) {
temp = get_sub(j - m * l, j - m * l + l - 1);
if(-- mp[temp] == 0) mp.erase(temp);
mp[get_sub(j, j + l- 1)] ++;
if(mp.size() == m) res ++;
}
}
cout << res << endl;
}
int main() {
ios::sync_with_stdio(false);cin.tie(0);cout.tie(nullptr);
// srand(time(0));
#ifdef ACM_LOCAL
freopen("input", "r", stdin);
freopen("output", "w", stdout);
#endif
init();
int o = 1;
// cin >> o;
while(o --) {
while(cin >> m >> l) {
cin >> s; n = s.size();
Hash[0] = 0;
for(int i = 1; i <= n; ++i)
Hash[i] = Hash[i - 1] * base + s[i - 1] - 'a';
solve();
}
}
return 0;
}