Järjestys

input/code.cpp: In function 'int main()':
input/code.cpp:37:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < s.sz(); i++) {
                         ~~^~~~~~~~
input/code.cpp:58:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < s.sz(); i++) {
                         ~~^~~~~~~~
input/code.cpp: In function 'void set_io(std::__cxx11::string)':
input/code.cpp:19:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen((filename + ".in").c_str(), "r", stdin);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
input/code.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen((filename + ".out").c_str(), "w", stdout);...

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define fi first
#define se second
#define sz size
#define rsz resize
#define ii pair<int,int>
#define vi vector<int>
#define vvi vector<vector<int>>
 
void set_io(string filename = "") {
    ios::sync_with_stdio(0);
    cin.tie(0);
 
    if (filename != "") {
        freopen((filename + ".in").c_str(), "r", stdin);
        freopen((filename + ".out").c_str(), "w", stdout);
    }
}
 
int T;
 
int main() {
	set_io("");
 
    cin >> T;
 
    while (T--) {
        string s; cin >> s;
 
        vector<int> bb(s.sz()), ab(s.sz()), aa(s.sz()), ba(s.sz());
 
        int ac = 0, bc = 0;
        for (int i = 0; i < s.sz(); i++) {
            ab[i] = ac;
            bb[i] = bc;
            if (s[i] == 'B') bc++;
            else ac++;
        }
 
        if (bc == 0 && ac == 0) {
            cout << 0 << endl;
            continue;
        }
 
        ac = 0, bc = 0;
        for (int i = s.sz() - 1; i >= 0; i--) {
            if (s[i] == 'A') ac++;
            else bc++;
            aa[i] = ac;
            ba[i] = bc;
        }
 
        int ms = INT_MAX;
        for (int i = 0; i < s.sz(); i++) {
            if (bb[i] == aa[i]) ms = min(ms, bb[i]);
        }
        cout << ms << endl;
    }
}

Test 1

Verdict: WRONG ANSWER