Submission #1118024

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118024		vjudge1	Match (CEOI16_match)	C++17	37 / 100	391 ms	524288 KiB

match

#include <bits/stdc++.h>
using namespace std;

#define SPEED ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
#define ALL(x) x.begin(), x.end()
#define intt long long
#define pb push_back
// #define endl "\n"

const int sz = 3e6 + 5, L = 20;

intt dp[sz][27];

bool valid(string& s) {
    stack<char>st;
    for(int i = 0; i < s.size(); i++) {
        if(!st.empty() && st.top() == s[i]) {
            st.pop();
        } else{
            st.push(s[i]);
        }
    }
    return st.empty();
}

string ans(sz, 'a');

void rec(intt l, intt r, string s) {
    if(l < r) {
        intt pos = dp[r][s[l] - 'a'];
        // cout << l << " " << r << " " << pos << endl;;
        ans[l - 1] = '(';
        ans[pos - 1] = ')';
        rec(l + 1, pos - 1, s);
        rec(pos + 1, r, s);
    }
}

void solve() {
    string s;
    cin >> s;
    int n = s.size();
    if(!valid(s)) {
        cout << -1 << endl;
        return;
    }
    ans.resize(n);
    // cout << "n" << endl;
    s = '?' + s;
    bool ok = true;
    for(int i = 1; i <= n; i++) {
        for(int j = 0; j < 26; j++) {
            // cout << i << " " << s[i] << " " << char(j + 'a') << endl;
            if(s[i] == char('a' + j)) {
                // if(i == 2 && s[i] == 'b') cout << j << endl;
                dp[i][j] = i;
            } else {
                if(dp[i-1][s[i]-'a'] > 0) dp[i][j] = dp[dp[i-1][s[i] - 'a']-1][j]; 
            }
        }
    }
    // for(int i = 1; i <= n + 1; i++) {
    //     for(int j = 0; j < 26; j++) {  
    //         cout << dp[i][j] << " ";
    //     }
    //     cout << endl;
    // }
    // cout << "n" << endl;

    rec(1, n, s);

    // cout << "n" << endl;

    if(ok == false ) {
        cout << -1 << endl;
    } else  {
        cout << ans << endl;
    }
}

int main() {
    SPEED;
    intt tst = 1;
    // cin >> tst;
    while (tst--) {
        solve();
    }
}

Compilation message (stderr)

match.cpp: In function 'bool valid(std::string&)':
match.cpp:16:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |     for(int i = 0; i < s.size(); i++) {
      |                    ~~^~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 27 / 27
• Subtask 3: 0 / 63