Submission #409891

#	Time	Username	Problem	Language	Result	Execution time	Memory
409891		CaroLinda	The short shank; Redemption (BOI21_prison)	C++14	35 / 100	119 ms	45744 KiB

prison

#include <bits/stdc++.h>

const int MAXN = 4010 ;

using namespace std ;

int N , D , T , toGet, toFill = 1 ;
int t[MAXN] ;
int dp[2][MAXN]; 
int cost[MAXN][MAXN] ;

void solve(int l, int r, int optmin , int optmax )
{
	if(l > r) return ;

	int mid = (l+r)>>1 ;
	int opt = optmin ;
	dp[toFill][mid] = cost[opt][mid]+dp[toGet][opt-1] ;

	for(int i = optmin+1 ; i <= min(mid,optmax) ; i++ )
	{
		int newCost = cost[i][mid] + dp[toGet][i-1] ;
		if(newCost >= dp[toFill][mid]) continue ;
		opt = i ;
		dp[toFill][mid] = newCost ;
	}

	solve(l, mid-1, optmin, opt ) ;
	solve(mid+1, r, opt, optmax  );
}

int main()
{
	scanf("%d %d %d", &N, &D, &T  ) ;
	for(int i = 1 ; i <= N ; i++ ) scanf("%d", &t[i] ) ;

	for(int i = 1 ; i <= N ; i++ )
	{
		int s = t[i]+1 ;
		cost[i][i] = t[i] <= T ;

		for(int j = i+1 ; j <= N ; j++ , s++ )
		{
			s = min(s, t[j] ) ;
			cost[i][j] = cost[i][j-1]+(s <= T ) ;
		}

	}

	for(int i = 1 ; i <= N ; i++ ) dp[0][i] = cost[1][i] ;
	for(int i = 1 ; i <= D ; i++ , swap(toGet, toFill) ) 
	{
		for(int j = 1 ; j <= i ; j++ ) dp[toFill][j] = dp[toGet][j] ;
		solve(i+1, N, i+1, N ) ;
	}

	printf("%d\n", dp[toGet][N] ) ;

}		

Compilation message (stderr)

prison.cpp: In function 'int main()':
prison.cpp:34:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |  scanf("%d %d %d", &N, &D, &T  ) ;
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
prison.cpp:35:38: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |  for(int i = 1 ; i <= N ; i++ ) scanf("%d", &t[i] ) ;
      |                                 ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 0 / 10
• Subtask 3: 20 / 20
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20