Submission #524494

#	Time	Username	Problem	Language	Result	Execution time	Memory
524494		Jarif_Rahman	Necklace (Subtask 1-3) (BOI19_necklace1)	C++17	45 / 85	1584 ms	108884 KiB

necklace

#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

vector<str> lex(str s){
    int n = s.size();
    char a = *min_element(s.begin(), s.end());
    vector<int> c;
    for(int i = 0; i < n; i++) if(s[i] == a) c.pb(i);
    
    vector<str> rt;

    auto startswith = [&s, &n](int k){
        str rt = "";
        for(int i = k; i < n; i++) rt+=s[i];
        for(int i = 0; i < k; i++) rt+=s[i];
        return rt;
    };

    if(c.size() == 1) return {startswith(c[0])};

    int mn = 1e9, k = -1;
    for(int i = 0; i < c.size(); i++){
        int ii = (i+1)%c.size();
        int cur = c[i]+1;
        cur+=n-c[ii];
        if(cur < mn) mn = cur, k = ii;
    }

    if(s.size()%2 == 0 && s.size()/2 == mn-1){
        return {startswith(c[k]), startswith(c[(k-1+c.size())%c.size()])};
    }
    else return {startswith(c[k])};
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    str s1, s2; cin >> s1 >> s2;
    int n = s1.size(), m = s2.size();

    unordered_map<str, pair<int, int>> mp;

    for(int i = 0; i < n; i++) for(int j = i; j < n; j++){
        str ss = "";
        for(int k = i; k <= j; k++) ss+=s1[k];
        for(str h: lex(ss)){
            if(mp.find(h) == mp.end() || mp[h].f < j-i+1) mp[h] = {j-i+1, i};
        }
        reverse(ss.begin(), ss.end());
        for(str h: lex(ss)){
            if(mp.find(h) == mp.end() || mp[h].f < j-i+1) mp[h] = {j-i+1, i};
        }
    }

    int ans = 0, a = 0, b = 0;

    for(int i = 0; i < m; i++) for(int j = i; j < m; j++){
        str ss = "";
        for(int k = i; k <= j; k++) ss+=s2[k];
        for(auto h: lex(ss)){
            if(mp[h].f > ans) ans = mp[h].f, a = mp[h].sc, b = i;
        }
        reverse(ss.begin(), ss.end());
        for(auto h: lex(ss)){
            if(mp[h].f > ans) ans = mp[h].f, a = mp[h].sc, b = i;
        }
    }

    cout << ans << "\n";
    cout << a << " " << b << "\n";
}

Compilation message (stderr)

necklace.cpp: In function 'std::vector<std::__cxx11::basic_string<char> > lex(str)':
necklace.cpp:27:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |     for(int i = 0; i < c.size(); i++){
      |                    ~~^~~~~~~~~~
necklace.cpp:34:38: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   34 |     if(s.size()%2 == 0 && s.size()/2 == mn-1){
      |                           ~~~~~~~~~~~^~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 20 / 20
• Subtask 3: 0 / 40