Submission #577097

#	Time	Username	Problem	Language	Result	Execution time	Memory
577097		amunduzbaev	Tortoise (CEOI21_tortoise)	C++17	0 / 100	79 ms	196468 KiB

tortoise

#include "bits/stdc++.h"
using namespace std;
 
#define ar array
typedef int64_t ll;

const int N = 5005;
const int inf = 1e9;
int dp[2][N][N], a[N];
int l[N], r[N];

signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int n; cin>>n;
	for(int i=0;i<n;i++){
		l[i] = n;
		cin>>a[i];
		if(a[i] == -1) l[i] = 0;
		else if(i) l[i] = l[i-1] + 1;
	}
	for(int i=n-1;~i;i--){
		r[i] = n;
		if(a[i] == -1) r[i] = 0;
		else if(i + 1 < n) r[i] = r[i+1] + 1;
	}
	
	memset(dp, 100, sizeof dp);
	dp[0][0][0] = 0;
	int res = 0;
	for(int i=0;i<=n;i++){
		for(int x=0;x<=n;x++){
			dp[0][i+1][x] = min(dp[0][i+1][x], dp[0][i][x] + 1);
			if(a[i+1] == -1) dp[0][i+1][x] = min(dp[0][i+1][x], dp[1][i][x] + 1);
			dp[1][i+1][x] = min(dp[1][i+1][x], dp[1][i][x] + 1);
			for(int z=1, is=1;is && z <= a[i];z++){ is = 0;
				if(dp[0][i][x] + (z - 1) * 2 * min(l[i], r[i])<=2*i){
					is = 1;
					dp[0][i + 1][x + z] = min(dp[0][i + 1][x + z], dp[0][i][x] + min(z * 2 * l[i] + 1, z * 2 * r[i] - 1));
					dp[1][i + 1][x + z] = min(dp[1][i + 1][x + 1], dp[0][i][x] + (z - 1) * 2 * min(l[i], r[i]) + 1);
				}
			}
			if(dp[0][i][x] < inf || dp[1][i][x] < inf) res = max(res, x);
		}
	}
	
	ll tot = 0;
	for(int i=0;i<n;i++){
		if(~a[i]) tot += a[i];
	}
	
	//~ cout<<tot<<" "<<res<<"\n";
	cout<<tot - res<<"\n";
}
 

• Subtask 1: 0 / 8
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 25
• Subtask 5: 0 / 27