Submission #2707462

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Source Code Expand

#include <iostream>
#include <string>
#include <algorithm>
#include <set>

int main() {
    std::string s, ret;
    int k;
    std::cin >> s >> k;

    char smallest[5] = { 'z', 'z', 'z', 'z', 'z' };
    for (auto c : s) {
        for (int i = 0; i < 5; i++) {
            if (smallest[i] == c) break;
            if (smallest[i] > c) {
                for (int j = 4; j > i; j--) {
                    smallest[j] = smallest[j-1];
                }
                smallest[i] = c;
                break;
            }
        }
    }
    
    std::set<std::string> sset;
    for (int i = 0; i < 5; i++) {
        for (int j = 0; j < s.length(); j++) {
            if (s[j] == smallest[i]) {
                int limit = std::min(k, (int)s.length() - j);
                for (int l = 1; l <= limit; l++){
                    sset.insert(std::string(s, j, l));
                }
            }
        }
        if (sset.size() >= k) break;
    }

    for (auto& str : sset) {
        if (--k == 0) std::cout << str << std::endl;
    }
    
    return 0;
}

Submission Info

Judge Result