Submission #22825025

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Source Code Expand

#include <bits/stdc++.h>

#define rep(i, n) for (auto i = 0; i < n; ++i)
#define ALL(a) a.begin(), a.end()

using namespace std;

using ll = long long int;

const int MOD_NUM = 1e9 + 7;

// 組み合わせ数(余り無し)
ll combination(ll n, ll r) {
    ll num = 1;
    for (auto i = 1; i <= r; i++) {
        num = num * (n - i + 1) / i;
    }
    return num;
}

int main() {
    // Input
    int A, B;
    ll K;
    cin >> A >> B >> K;

    // Process
    string ans;
    int a = A;
    int b = B;
    ll k = K - 1;
    rep(i, A + B) {
        ll ncb = combination(a + b - 1, b);
        if (k >= ncb) {
            ans += "b";
            k -= ncb;
            b--;
        } else {
            ans += "a";
            a--;
        }
    }

    // Output
    cout << ans << endl;

    return 0;
}

Submission Info

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