Submission #927520

#	Time	Username	Problem	Language	Result	Execution time	Memory
927520		Whisper	Mate (COCI18_mate)	C++17	30 / 100	341 ms	21584 KiB

mate

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
using T = tuple<ll, ll, ll>;

#define int long long
#define Base 41
#define sz(a) (int)a.size()
#define FOR(i, a, b) for ( int i = a ; i <= b ; i++ )
#define FORD(i, a, b) for (int i = b; i >= a; i --)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPD(i, n) for (int i = n - 1; i >= 0; --i)
#define all(x) x.begin() , x.end()
#define pii pair<int , int>
#define fi first
#define se second
#define Lg(x) 31 - __builtin_clz(x)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)

constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int MAX = 2e3 + 5;
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void setupIO(){
    #define name "Whisper"
    //Phu Trong from Nguyen Tat Thanh High School for gifted student
    srand(time(NULL));
    cin.tie(nullptr)->sync_with_stdio(false); cout.tie(nullptr);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    cout << fixed << setprecision(10);
}

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
string s;
int numQuery, maxLen;

int inv[MAX], fac[MAX];
int power(int a, int exp){
    int res = 1;
    for ( ; exp > 0; exp >>= 1, a = (1ll * a * a) % Mod) if(exp & 1){
        res = (1ll * res * a) % Mod;
    }
    return res;
}
void genFac(int n){
    inv[0] = fac[0] = 1;
    for (int i = 1; i <= n; ++i){
        fac[i] = fac[i - 1] *i % Mod;
    }
    inv[n] = power(fac[n], Mod - 2);
    for (int i = n; i >= 1; --i) inv[i - 1] = 1ll * inv[i] * i % Mod;
}

int C(int n, int k){
    assert(n >= k);
    return 1ll * fac[n] * inv[n - k] % Mod * inv[k] % Mod;
}
int A(int n, int k){
    assert(n >= k);
    return 1ll * fac[n] * inv[n - k] % Mod;
}
int cnt[26], ans[26][26][MAX];

void add(int &x, int y){
    x += y;
    if (x >= Mod) x -= Mod;
}

void Whisper(){
    cin >> s >> numQuery;
    int nLen = sz(s);
    genFac(nLen);
    for (int i = nLen - 1; i >= 0; --i){
        int a = s[i] - 'a';
        REP(b, 26) FOR(l, 2, i + 2){
            add(ans[a][b][l], C(i, l - 2) * cnt[b]);
        }
        cnt[a]++;
    }
    for (int i = 1; i <= numQuery; ++i){
        int maxLen; string t;
        cin >> maxLen >> t;
        int a = t[0] - 'a', b = t[1] - 'a';
        cout << ans[a][b][maxLen] << '\n';
    }
}


signed main(){
    setupIO();
    int Test = 1;
//    cin >> Test;
    for ( int i = 1 ; i <= Test ; i++ ){
        Whisper();
        if (i < Test) cout << '\n';
    }
}

• Subtask 1: 30 / 100