Submission #1215271

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215271		salmon	Chorus (JOI23_chorus)	C++20	0 / 100	0 ms	328 KiB

chorus

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

int N, K;
pair<long double,int> memo[5100];
long long int pre[5100][5100];
int in[10100];
int bin[10100];
string s;

long long int inf = 1.1e18;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	
	cin >> N >> K;
	cin >> s;
	
	int a = 1;
	int b = 1;
	
	for(int i = 0; i < N * 2; i++){
		if(s[i] == 'A'){
			bin[a] = b;
			a++;
		}
		else{
			b++;
		}
	}
	
	
	for(int i = 1; i <= N; i++){
		pre[i][i - 1] = 0;
		
		for(int j = i; j <= N; j++){
			pre[i][j] = pre[i][j - 1] + max(0,bin[j] - i );
		}
	}
	
	long double s = 0;
	long double e = 1e13;
	
	for(int i = 0; i < 100; i++){
		long double m = (s + e)/2;
		
		for(int i = 0; i <= N; i++){
			memo[i] = {inf,1};
		}
		memo[0] = {0,0};
		
		for(int i = 1; i <= N; i++){
			for(int k = i; k >= 1; k--){
				memo[i] = min(memo[i], {memo[k - 1].first + pre[k][i] + m, memo[k - 1].second + 1} );
			}
		}
		
		/*for(int i = 1; i <= N; i++){
			printf("%lld\n",memo[i][K]);
		}*/
		
		if(i == 100) break;
		
		if(memo[N].second > K){
			s = m;
		}
		else{
			e = m;
		}
	}
	
	
	printf("%lld",(long long int)(memo[N].first - memo[N].second * s + 0.1) );
}
 

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