Submission #3392296

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Source Code Expand

#include <bits/stdc++.h>

int main() {
    int n, k;
    std::string s;
    std::cin >> n >> k >> s;
    std::bitset<210000> b;
    // A -> 0, B -> 1
    for (auto i = 0; i < s.size(); i++) {
        b[i] = s[i] == 'B';
    }
    for (int i = 0; i < std::min(2 * n, k); i++) {
        if (b[0]) {
            b >>= 1;
            b = ~b;
            b[n - 1] = false;
        } else {
            b[0] = true;
        }
    }

    if (2 * n >= k) {
        for (int i = 0; i < n; i++) std::cout << (b[i] ? 'B' : 'A');
    } else {
        if (n % 2) {
            std::cout << ((2 * n - k) % 2 ^ b[0] ? 'B' : 'A');
            for (int i = 1; i < n; i++) std::cout << (i % 2 ? 'B' : 'A');
        } else {
            for (int i = 0; i < n; i++) std::cout << (i % 2 ? 'A' : 'B');
        }
    }
    std::cout << std::endl;

    return 0;
}

Submission Info

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