제출 #769984

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
769984		raysh07	스탬프 수집 (JOI16_ho_t2)	C++17	100 / 100	9 ms	8372 KiB

2016_ho_t2

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define f first
#define s second

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

void Solve() 
{
    int n; cin >> n;
    string s; cin >> s;
    vector <int> a(n + 1);
    for (int i = 1; i <= n; i++){
        if (s[i - 1] == 'J') a[i] = 1;
        else if (s[i - 1] == 'O') a[i] = 2;
        else a[i] = 3;
    }
    
    vector<vector<int>> dp(n + 1, vector<int>(4, 0));
    dp[0][0] = 1;
    for (int i = 1; i <= n; i++){
        for (int j = 0; j <= 3; j++){
            dp[i][j] += dp[i - 1][j];
            if (a[i] == j + 1) dp[i][j + 1] += dp[i - 1][j];
        }
    }
    
    int add = dp[n][3];
    
    int ans = 0;
    int c1 = 0, c2 = 0;
    
    for (int i = 1; i <= n; i++){
        if (a[i] == 2){
            c1++;
        } else if (a[i] == 3) c2 += c1;
    }
    
    ans = max(ans, c2);
    c1 = 0, c2 = 0;
    
    for (int i = n; i >= 1; i--){
        if (a[i] == 2){
            c1++;
        } else if (a[i] == 1) c2 += c1;
    }
    
    ans = max(ans, c2);
    
    int a1 = 0, a2 = 0;
    for (int i = 1; i <= n; i++){
        a1 += a[i] == 3;
    }
    
    for (int i = 1; i <= n; i++){
        a2 += a[i] == 1;
        a1 -= a[i] == 3;
        
        ans = max(ans, a1 * a2);
    }
    
   // cout << add << "\n";
    cout << ans + add << "\n";
}

int32_t main() 
{
    auto begin = std::chrono::high_resolution_clock::now();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
 //   cin >> t;
    for(int i = 1; i <= t; i++) 
    {
        //cout << "Case #" << i << ": ";
        Solve();
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 50 / 50