Submission #16563738

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Source Code Expand

#include <algorithm>
#include <cmath>
#include <cstring>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

typedef long long ll;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
constexpr double PI = 3.141592653589793;
constexpr int INF = 1e9 + 10;
constexpr ll INFL = 1e18 + 10;

template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

using namespace std;
// cout << setprecision(20) << ans << "\n";

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

  string s;
  cin >> s;
  if (s.size() != 26) {
    vector<int> seen(26, 0);
    for (char c : s) {
      seen[c - 'a'] = 1;
    }
    for (int i = 0; i < 26; i++) {
      if (!seen[i]) {
        s.push_back('a' + i);
        cout << s << "\n";
        return 0;
      }
    }
  }

  set<char> g;
  while (s.size()) {
    char c = s.back();
    s.pop_back();
    auto it = g.upper_bound(c);
    if (it != g.end()) {
      s += *it;
      cout << s << '\n';
      return 0;
    }
    g.insert(c);
  }
  cout << -1 << "\n";

  return 0;
}

Submission Info

Judge Result