Submission #742460

#	Time	Username	Problem	Language	Result	Execution time	Memory
742460		hmm789	Tortoise (CEOI21_tortoise)	C++14	0 / 100	1 ms	212 KiB

tortoise

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF 1000000000000000000

int32_t main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	int n, ans = INF;
	cin >> n;
	int a[n], lt[n], rt[n], dp[2*n+1][n], pref[n];
	for(int i = 0; i < n; i++) cin >> a[i];
	lt[0] = a[0]==-1?0:INF;
	for(int i = 1; i < n; i++) {
		lt[i] = lt[i-1];
		if(a[i] == -1) lt[i] = i;
	}
	rt[n-1] = a[n-1]==-1?n-1:INF;
	for(int i = n-2; i >= 0; i--) {
		rt[i] = rt[i+1];
		if(a[i] == -1) rt[i] = i;
	}
	pref[0] = max(a[0], 0LL);
	for(int i = 1; i < n; i++) pref[i] = pref[i-1]+max(a[i], 0LL);
	for(int i = 0; i <= 2*n; i++) {
		for(int j = 0; j < n; j++) {
			dp[i][j] = INF;
		}
	}
	for(int i = 0; i <= 2*n; i++) {
		for(int j = 0; j < n; j++) {
			if(a[j] == -1) continue;
			if(i < j) continue;
			dp[i][j] = max(min(dp[i][j], pref[j]-1), 0LL);
			int sm = 0;
			for(int k = j; k < n; k++) {
				if(k > j) sm += max(a[k], 0LL);
				if(a[k] == -1) continue;
				int dist = min(abs(j-lt[j])+abs(k-lt[j]), abs(rt[j]-j)+abs(rt[j]-k));
				if(dist+i > 2*n) continue;
				if(dist+i > 2*k) continue;
				if(k == j) dp[dist+i][k] = min(dp[dist+i][k], max(dp[i][j]-1, 0LL));
				else dp[dist+i][k] = min(dp[dist+i][k], dp[i][j]+max(sm-1, 0LL));
			}
			ans = min(ans, dp[i][j]+pref[n-1]-pref[j]);
		}
	}
	cout << ans;
}

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