Submission #1147140

#	Time	Username	Problem	Language	Result	Execution time	Memory
1147140		qrn	Match (CEOI16_match)	C++20	100 / 100	16 ms	23368 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, s;

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

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

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

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