Submission #612492

#	Time	Username	Problem	Language	Result	Execution time	Memory
612492		drdilyor	Match (CEOI16_match)	C++17	37 / 100	1510 ms	63916 KiB

match

#include <bits/stdc++.h>
#ifdef ONPC
    #include "t_debug.cpp"
#else
    #define debug(...) 42
#endif
#define sz(a) ((int)(a).size())
using namespace std;
using ll = long long;
const int INF = 1e9;
const ll INFL = 1e18;
const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rng(RANDOM);
template<typename T, typename U> istream& operator>>(istream& is, pair<T, U>& p) { return is >> p.first >> p.second; }
const int N = 2001, LOGN = 17, MOD = 1e9+7;

string solve(const string& s) {
    int n = s.size();
    string res(n, '?');
    vector<int> match[26];

    int parent[N][N], memo[N][N];
    memset(parent, 0, sizeof(parent));
    memset(memo, -1, sizeof(memo));

    function<bool(int,int)> dp = [&](int beg,int end)->bool { // [beg, end)
        if (beg > end) return true;
        if ((end - beg + 1) % 2) return false;
        if (memo[beg][end] != -1) return memo[beg][end];
        memo[beg][end] = false;

        for (int i = beg+1; i <= end; i++) {
            if (s[i] == s[beg] && dp(beg+1, i-1) && dp(i+1, end)) {
                parent[beg][end] = i;
                memo[beg][end] = true;
            }
        }
        return memo[beg][end];
    };

    function<void(int,int)> construct = [&](int beg, int end) {
        if (beg > end) return;
        res[beg] = '(';
        res[parent[beg][end]] = ')';
        construct(beg+1, parent[beg][end] - 1);
        construct(parent[beg][end]+1, end);
    };

    if (!dp(0, n-1)) return "-1";
    construct(0, n-1);
    return res;
}

string solve_2(const string& s) {
    int n = s.size();
    string res(n, '?');
    function<bool(int)> brute = [&](int i) {
        if (i < n) {
            res[i] = '(';
            if (brute(i+1)) return true;
            res[i] = ')';
            return brute(i+1);
        } else {
            vector<int> matching(n, -1);
            vector<int> cur;
            for (int i = 0; i < n; i++) {
                if (res[i] == '(') {
                    cur.push_back(i);
                } else {
                    if (cur.empty()) return false;
                    matching[i] = cur.back();
                    matching[cur.back()] = i;
                    cur.pop_back();
                }
            }
            if (!cur.empty()) return false;
            for (int i = 0; i < n; i++) {
                if (s[i] != s[matching[i]]) return false;
                int depth = 0;
                for (int j = i+1; j < matching[i]; j++) {
                    if (res[j] == '(') depth++;
                    else depth--;
                    if (depth < 0) return false;
                }
                if (depth != 0) return false;
            }
            return true;
        }
    };
    return brute(0) ? res : "-1";
}

signed main() {
    int t = 1;
    #ifdef ONPC
    cin >> t;
    #endif
    while (t-- && cin) {
        string s; cin >> s;
        if (!cin) break;
        #ifdef ONPC
        cout << "Case " << s << '\n';
        string res1 = solve(s), res2 = solve_2(s);
        cout << res1 << endl;
        if (res1 != res2) {
            cout << res2 << endl;
            cout << "Case " << s << '\n';
            assert(false);
        }
        #else
        cout << solve(s);
#endif
    }
    return 0;
}

/*
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*/

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