Submission #1144465

#	Time	Username	Problem	Language	Result	Execution time	Memory
1144465		not_amir	parentrises (BOI18_parentrises)	C++20	72 / 100	60 ms	55880 KiB

parentrises

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

string solve1(string s = "") {
    if (s.empty())
        cin >> s;
    int n = s.length();
    stack<int> pos, neg;
    int pcnt = 0;
    string ans(n, 'G');
    for (int i = 0; i < n; i++) {
        if (s[i] == '(')
            pos.push(i), pcnt++;
        else {
            neg.push(i);
            if (pcnt == 0) {
                if (neg.size() < 2)
                    return "impossible";
                ans[neg.top()] = 'R';
                neg.pop();
                ans[neg.top()] = 'B';
                neg.pop();
            }
            else
                pcnt--;
        }
    }
    if (2 * pcnt > pos.size())
        return "impossible";
    for (int i = 0; i < pcnt; i++) {
        ans[pos.top()] = 'R';
        pos.pop();
        ans[pos.top()] = 'B';
        pos.pop();
    }
    int sum1 = 0, sum2 = 0;
    for (int i = 0; i < n; i++) {
        if (ans[i] == 'R' || ans[i] == 'G')
            sum1 += s[i] == '(' ? 1 : -1;
        if (ans[i] == 'B' || ans[i] == 'G')
            sum2 += s[i] == '(' ? 1 : -1;
        if (sum1 < 0 || sum2 < 0)
            return "impossible";
    }
    return ans;
}

constexpr int MAXN = 301, MOD = 1e9 + 7;

int solve2() {
    static int mem[MAXN], dp[MAXN + 5][MAXN + 5][MAXN + 5];
    if (dp[0][0][0] == 0) {
        dp[0][0][0] = 1;
        for (int i = 1; i < MAXN; i++) {
            for (int j = 0; j <= i; j++) {
                for (int k = 0; k <= i; k++) {
                    if (k)
                        dp[i][j][k] += dp[i - 1][j][k - 1], dp[i][j][k] %= MOD;
                    else {
                        dp[i][j][k] += dp[i - 1][j + 1][k];
                        dp[i][j][k] %= MOD;
                        if (j)
                            dp[i][j][k] += dp[i - 1][j - 1][k + 1], dp[i][j][k] %= MOD;
                    }
                    if (j > 2)
                        dp[i][j][k] += dp[i - 1][j - 3][k + 2], dp[i][j][k] %= MOD;
                }
            }
        }
    }
    int n;
    cin >> n;
    if (mem[n])
        return mem[n];
    int ans = 0;
    for (int j = 0; j < MAXN; j++)
        ans += dp[n][j][0];
    return mem[n] = ans;
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int p, t;
    cin >> p >> t;
    while (t--) {
        if (p == 1)
            cout << solve1() << '\n';
        if (p == 2)
            cout << solve2() << '\n';
    }
}

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 6 / 6
• Subtask 4: 28 / 28
• Subtask 5: 6 / 6
• Subtask 6: 16 / 16
• Subtask 7: 0 / 28