Submission #796424

#	Time	Username	Problem	Language	Result	Execution time	Memory
796424		Johann	Chorus (JOI23_chorus)	C++14	40 / 100	7031 ms	392380 KiB

chorus

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

typedef long long ll;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

const ll INF = 1LL << 60;
int N, K;
vi S;
int cnt[2];
vi pos[2];
vvi dp;
vvi trans;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> N >> K;
    string SS;
    cin >> SS;
    S.resize(2 * N);
    for (int foo = 0; foo < 2; ++foo)
        pos[foo].assign(N, -1);
    for (int i = 0; i < 2 * N; ++i)
    {
        S[i] = (SS[i] == 'B');
        pos[S[i]][cnt[S[i]]++] = i;
    }

    trans = vvi(N + 1, vi(N + 1, INF));
    for (int i = 1; i <= N; ++i)
    {
        trans[i][i] = 0;
        int border = 2 * i;
        for (int j = i; j < N; ++j)
            trans[i][j + 1] = trans[i][j] + max(0LL, pos[0][j] - border++);
    }

    dp = vvi(N + 1, vi(K + 1, INF));

    dp[0][0] = 0;
    dp[0][1] = 0;
    for (int i = 0; i < N; ++i)
        dp[i + 1][1] = dp[i][1] + pos[0][i] - i;

    for (int k = 2; k <= K; ++k)
    {
        int idx = k - 1;
        for (int j = k; j <= N; ++j)
        {
            for (int i = idx; i < j; ++i)
                if (dp[i][k - 1] + trans[i][j] <= dp[idx][k - 1] + trans[idx][j])
                    idx = i;
            // while (idx + 1 < j && dp[idx][k - 1] + trans[idx][j] >= dp[idx + 1][k - 1] + trans[idx + 1][j])
            // ++idx;

            dp[j][k] = dp[idx][k - 1] + trans[idx][j];
        }
    }

    cout << dp[N][K] << endl;

    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 24 / 24
• Subtask 3: 0 / 21
• Subtask 4: 0 / 26
• Subtask 5: 0 / 13