Submission #906437

#	Time	Username	Problem	Language	Result	Execution time	Memory
906437		LucaIlie	Chorus (JOI23_chorus)	C++17	40 / 100	7049 ms	193516 KiB

chorus

#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 5e3;
int a[MAX_N + 1];
long long sumA[MAX_N + 1], countLowerA[MAX_N + 1], sumLowerA[MAX_N + 1], minSwaps[MAX_N + 1][MAX_N + 1];

int main() {
    int n, k, swaps;

    cin >> n >> k;

    int countB = 0, countA = 0;
    swaps = 0;
    for ( int i = 0; i < 2 * n; i++ ) {
        char ch;
        cin >> ch;
        if ( ch == 'A' )
            countA++;
        else {
            countB++;
            swaps += max( 0, countB - countA );
            a[countB] = max( countA, countB );
            sumA[countB] = sumA[countB - 1] + a[countB];
            countLowerA[a[countB]]++;
            sumLowerA[a[countB]] += a[countB];
        }
    }
    for ( int i = 1; i <= n; i++ ) {
        countLowerA[i] += countLowerA[i - 1];
        sumLowerA[i] += sumLowerA[i - 1];
    }

    for ( int i = 1; i <= n; i++ )
        minSwaps[i][0] = n * n;
    for ( int l = 1; l <= k; l++ ) {
        for ( int i = 1; i <= n; i++ ) {
            minSwaps[i][l] = n * n;
            for ( int j = i - 1; j >= 0; j-- )
                minSwaps[i][l] = min( minSwaps[i][l], minSwaps[j][l - 1] + i * (countLowerA[i] - j) - (sumLowerA[i] - sumA[j]) );
        }
    }

    cout << swaps + minSwaps[n][k];

    return 0;
}

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