Submission #236997

#	Time	Username	Problem	Language	Result	Execution time	Memory
236997		Sorting	Match (CEOI16_match)	C++14	100 / 100	77 ms	17784 KiB

match

#include <bits/stdc++.h>

using namespace std;

#define ll long long

const ll k_Mods[2]{(ll)(1e9 + 7), (ll)(1e9 + 103)};
const ll k_Bases[2]{29, 43};

const int k_N = 1e5 + 7;

string s;
int n;

ll powers[2][k_N];

map<array<ll, 2>, vector<int>> c;
array<ll, 2> hash_arr[k_N];

bool check(string &curr, int pos, array<ll, 2> curr_hash){
    c[curr_hash].push_back(pos);
    hash_arr[pos] = curr_hash;

    if(curr == "" && pos == n)
        return true;
    if(curr.size() > (n - pos))
        return false;

    if(curr != "" && curr.back() == s[pos]){
        curr.pop_back();
        
        for(int i = 0; i <= 1; ++i){
            curr_hash[i] -= powers[i][curr.size()] * (s[pos] - 'a' + 1);
            curr_hash[i] %= k_Mods[i];
            if(curr_hash[i] < 0)
                curr_hash[i] += k_Mods[i];
        }

        bool answer = check(curr, pos + 1, curr_hash);
        curr += s[pos];

        return answer;
    }

    curr += s[pos];

    for(int i = 0; i <= 1; ++i){
        curr_hash[i] += powers[i][curr.size() - 1] * (s[pos] - 'a' + 1);
        curr_hash[i] %= k_Mods[i];
    }

    bool answer = check(curr, pos + 1, curr_hash);
    curr.pop_back();

    return answer;
}

char answer[k_N];
void solve(int l, int r){
    if(l > r)
        return;

    answer[l] = '(';

    vector<int> &v = c[hash_arr[l + 1]];
    int x = *(upper_bound(v.begin(), v.end(), r + 1) - 1);

    answer[x] = ')';

    solve(l + 1, x - 1);
    solve(x + 1, r);
}

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

    cin >> s;
    n = s.size();

    powers[0][0] = 1;
    powers[1][0] = 1;

    for(int i = 0; i <= 1; ++i)
        for(int j = 1; j <= n; ++j)
            powers[i][j] = (powers[i][j - 1] * k_Bases[i]) % k_Mods[i];

    string curr = "";
    if(!check(curr, 0, {0, 0})){
        cout << "-1\n";
        return 0;
    }

    solve(0, n - 1);

    for(int i = 0; i < n; ++i)
        cout << answer[i];
    cout << "\n";
}

Compilation message (stderr)

match.cpp: In function 'bool check(std::__cxx11::string&, int, std::array<long long int, 2>)':
match.cpp:26:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(curr.size() > (n - pos))
        ~~~~~~~~~~~~^~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 27 / 27
• Subtask 3: 63 / 63