Submission #49544351

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Source Code Expand

/**
 *  @the_hyp0cr1t3
 *  21.01.2024 17:33
**/
#include <bits/stdc++.h>

int main() {
    std::cin.tie(nullptr)->sync_with_stdio(false);

    int n;
    std::string s, t;
    std::cin >> n >> s >> t;

    std::array<std::array<int, 2>, 2> fst{{{n, n}, {n, n}}}, lst{{{-1, -1}, {-1, -1}}};
    for (int i = 0; i < n; i++) {
        lst[0][s[i] - 'A'] = i;
        lst[1][t[i] - 'A'] = i;
    }
    for (int i = n - 1; ~i; i--) {
        fst[0][s[i] - 'A'] = i;
        fst[1][t[i] - 'A'] = i;
    }

    if (lst[0][1] > lst[1][1] or fst[0][0] < fst[1][0]) {
        std::cout << -1 << '\n';
        return 0;
    }

    int ans = 0, cntA = 0;
    for (int i = 0; i < n; i++) {
        if (s[i] == t[i]) continue;
        ans++;
        if (t[i] == 'A') cntA++;
        else if (cntA) ans--, cntA--;
    }

    std::cout << ans << '\n';
}

Submission Info

Judge Result