Ositus

input/code.cpp: In function 'bool valid(int)':
input/code.cpp:25:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < s.sz(); i++) {
                     ~~^~~~~~~~
input/code.cpp:30:37: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
         if (mask & (1 << s.sz() - 2 - i)) open = vector<bool>(26, false);
                          ~~~~~~~~~~~^~~
input/code.cpp: In function 'int main()':
input/code.cpp:41:38: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
     for (int i = 0; i < (1 << s.sz() - 1); i++) {
                               ~~~~~~~^~~
input/code.cpp: In function 'void set_io(std::__cxx11::string)':
input/code.cpp:16:16: 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);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...

#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

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);
    }
}

string s;

bool valid(int mask) {
    vector<bool> open(26, false);
    for (int i = 0; i < s.sz(); i++) {
        int ci = s[i] - 'a';
        if (open[ci]) return false;
        open[ci] = true;

        if (mask & (1 << s.sz() - 2 - i)) open = vector<bool>(26, false);
    }
    return true;
}

int main() {
    set_io("");

    cin >> s;

    int ans = 0;
    for (int i = 0; i < (1 << s.sz() - 1); i++) {
        ans += valid(i);
    }
    cout << ans << endl;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: WRONG ANSWER

Test 6

Group: 3

Verdict: WRONG ANSWER

Test 7

Group: 3

Verdict: WRONG ANSWER