Submission #206703

#	Time	Username	Problem	Language	Result	Execution time	Memory
206703		Saboon	Collecting Stamps 3 (JOI20_ho_t3)	C++14	100 / 100	77 ms	72952 KiB

ho_t3

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;

const int maxn = 200 + 10;
const int inf= 1e9 + 1;

int L;
int dp[maxn][maxn][maxn], pd[maxn][maxn][maxn];
int x[maxn], t[maxn];

int dis(int x, int y){
	if (x > y)
		swap(x, y);
	return min(y - x, L - y + x);
}

int main(){
	ios_base::sync_with_stdio(false);
	int n;
	cin >> n >> L;
	for (int i = 1; i <= n; i++)
		cin >> x[i];
	for (int i = 1; i <= n; i++)
		cin >> t[i];
	int answer = 0;
	x[0] = 0, x[n + 1] = 0;
	memset(dp, 63, sizeof dp);
	memset(pd, 63, sizeof pd);
	dp[0][0][0] = pd[0][0][0] = 0;
	for (int i = 0; i <= n; i++){
		for (int j = 0; i + j <= n; j++){
			if (i + j == 0)
				continue;
			int iidx = i, jidx = n-j+1;
			for (int k = 0; k <= i + j; k++){
				if (j > 0){
					dp[i][j][k] = min(dp[i][j-1][k] + dis(x[jidx], x[jidx+1]), pd[i][j-1][k] + dis(x[jidx], x[iidx]));
					if (k > 0){
						if (dp[i][j-1][k-1] + dis(x[jidx], x[jidx+1]) <= t[jidx])
							dp[i][j][k] = min(dp[i][j][k], dp[i][j-1][k-1] + dis(x[jidx], x[jidx+1]));
						if (pd[i][j-1][k-1] + dis(x[jidx], x[iidx]) <= t[jidx])
							dp[i][j][k] = min(dp[i][j][k], pd[i][j-1][k-1] + dis(x[jidx], x[iidx]));
					}
				}
				if (i > 0){
					pd[i][j][k] = min(pd[i-1][j][k] + dis(x[iidx], x[iidx-1]), dp[i-1][j][k] + dis(x[iidx], x[jidx]));
					if (k > 0){
						if (pd[i-1][j][k-1] + dis(x[iidx], x[iidx-1]) <= t[iidx])
							pd[i][j][k] = min(pd[i][j][k], pd[i-1][j][k-1] + dis(x[iidx], x[iidx-1]));
						if (dp[i-1][j][k-1] + dis(x[iidx], x[jidx]) <= t[iidx])
							pd[i][j][k] = min(pd[i][j][k], dp[i-1][j][k-1] + dis(x[iidx], x[jidx]));
					}
				}
				if (dp[i][j][k] < inf or pd[i][j][k] < inf)
					answer = max(answer, k);
			}
		}
	}
	cout << answer << endl;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 75 / 75