Submission #332299

#	Time	Username	Problem	Language	Result	Execution time	Memory
332299		ChrisT	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	86 ms	67920 KiB

ho_t3

#include <bits/stdc++.h>
using namespace std;
int dp[205][205][205][2]; //[L][R][got][where]
int main () {
	int n,p;
	scanf ("%d %d",&n,&p);
	auto dist = [&] (int a, int b) {int d = abs(a-b); return min(d,p-d);};
	vector<int> pos(n+1), t(n+1);
	for (int i = 1; i <= n; i++) scanf ("%d",&pos[i]);
	for (int i = 1; i <= n; i++) scanf ("%d",&t[i]);
	memset(dp,0x3f,sizeof dp);
	dp[0][0][0][0] = dp[0][0][0][1] = 0; int ret = 0; ++n;
	for (int len = 2; len <= n; len++) {
		for (int st = 1 - len; st <= 0; st++) {
			int l = (st + n) % n, r = (l + len - 1) % n;
			for (int taken = 0; taken < len; taken++) {
				int l2 = (l + 1) % n, r2 = (r - 1 + n) % n;
				dp[l][r][taken][0] = min({dp[l][r][taken][0],dp[l2][r][taken][0] + dist(pos[l2],pos[l]), dp[l2][r][taken][1] + dist(pos[r],pos[l])});
				dp[l][r][taken][1] = min({dp[l][r][taken][1],dp[l][r2][taken][0] + dist(pos[l],pos[r]), dp[l][r2][taken][1] + dist(pos[r2],pos[r])});
				if (taken) {
					if (dp[l2][r][taken-1][0] + dist(pos[l2],pos[l]) <= t[l]) {
						dp[l][r][taken][0] = min(dp[l][r][taken][0],dp[l2][r][taken-1][0] + dist(pos[l2],pos[l]));
					}
					if (dp[l2][r][taken-1][1] + dist(pos[l],pos[r]) <= t[l]) {
						dp[l][r][taken][0] = min(dp[l][r][taken][0],dp[l2][r][taken-1][1] + dist(pos[l],pos[r]));
					}
					if (dp[l][r2][taken-1][0] + dist(pos[l],pos[r]) <= t[r]) {
						dp[l][r][taken][1] = min(dp[l][r][taken][1],dp[l][r2][taken-1][0] + dist(pos[l],pos[r]));
					}
					if (dp[l][r2][taken-1][1] + dist(pos[r2],pos[r]) <= t[r]) {
						dp[l][r][taken][1] = min(dp[l][r][taken][1],dp[l][r2][taken-1][1] + dist(pos[r2],pos[r]));
					}
				}
				if (min(dp[l][r][taken][0],dp[l][r][taken][1]) <= 1'000'000'000) ret = max(ret,taken);
			}
		}
	}
	printf ("%d\n",ret);
	return 0;
}

Compilation message (stderr)

ho_t3.cpp: In function 'int main()':
ho_t3.cpp:6:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 |  scanf ("%d %d",&n,&p);
      |  ~~~~~~^~~~~~~~~~~~~~~
ho_t3.cpp:9:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |  for (int i = 1; i <= n; i++) scanf ("%d",&pos[i]);
      |                               ~~~~~~^~~~~~~~~~~~~~
ho_t3.cpp:10:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |  for (int i = 1; i <= n; i++) scanf ("%d",&t[i]);
      |                               ~~~~~~^~~~~~~~~~~~

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