제출 #741489

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
741489		arnold518	Chorus (JOI23_chorus)	C++17	16 / 100	2 ms	340 KiB

chorus

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 1e6;
const ll INF = 1e12;

int N, K;
char S[MAXN*2+10];
int A[MAXN+10], C[MAXN+10];
ll B[MAXN+10];
ll ans;

ll f(int l, int r)
{
	if(C[r]<l) return 0;
	return (ll)r*(C[r]-l+1)-(B[C[r]]-B[l-1]);
}

pll dp[MAXN+10];

ll solve(ll lambda)
{
	dp[0]={0, 0};
	for(int i=1; i<=N; i++)
	{
		dp[i]={9e18, 0};
		for(int j=0; j<i; j++)
		{
			dp[i]=min(dp[i], {dp[j].first+lambda+2*f(j+1, i), dp[j].second+1});
		}
	}
	return dp[N].second;
}

int main()
{
	scanf("%d%d", &N, &K);
	scanf(" %s", S+1);

	int t=0, k=0;
	for(int i=1; i<=N+N; i++)
	{
		if(S[i]=='A') k++;
		else A[++t]=k;
	}
	for(int i=1; i<=N; i++)
	{
		if(A[i]<i)
		{
			ans+=i-A[i];
			A[i]=i;
		}
		B[i]=B[i-1]+A[i];
	}

	for(int i=1, j=1; i<=N; i++)
	{
		for(; j<=N && A[j]<i; j++);
		C[i]=j-1;
	}

	ll lo=0, hi=INF;
	while(lo+1<hi)
	{
		ll mid=lo+hi>>1;
		if(solve(mid*2+1)<K) hi=mid;
		else lo=mid;
	}
	solve(hi*2);
	printf("%lld\n", ans+dp[N].first/2-K*hi);
}

컴파일 시 표준 에러 (stderr) 메시지

chorus.cpp: In function 'int main()':
chorus.cpp:69:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   69 |   ll mid=lo+hi>>1;
      |          ~~^~~
chorus.cpp:41:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |  scanf("%d%d", &N, &K);
      |  ~~~~~^~~~~~~~~~~~~~~~
chorus.cpp:42:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |  scanf(" %s", S+1);
      |  ~~~~~^~~~~~~~~~~~

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