Submission #485061

#	Time	Username	Problem	Language	Result	Execution time	Memory
485061		socho	Collecting Stamps 3 (JOI20_ho_t3)	C++14	100 / 100	127 ms	129560 KiB

ho_t3

#include <bits/stdc++.h>
using namespace std;
void fast() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
}
void ran() {
	srand(chrono::steady_clock::now().time_since_epoch().count());
}
long long get_rand() {
	long long a = rand();
	long long b = rand();
	return a * (RAND_MAX + 1ll) + b;
}
void usaco() {
	freopen("problem.in", "r", stdin); 
	freopen("problem.out", "w", stdout);
}
template<typename T>
using min_pq = priority_queue<T, vector<T>, greater<T>>;
#define endl '\n'
// #define double long double
#define int long long
// const int MOD = 1000 * 1000 * 1000 + 7;
// const int MOD = 998244353;
// #define cerr if(0) cerr
#define debug(x) cerr << #x << ": " << x << endl;

int n, len;
const int MXN = 205;
int pos[MXN], by[MXN];
 
int dp[MXN][MXN][2][MXN];
 
priority_queue<pair<int, pair<pair<int, int>, pair<int, int>>>, vector<pair<int, pair<pair<int, int>, pair<int, int>>>>, greater<pair<int, pair<pair<int, int>, pair<int, int>>>>> proc;
 
bool can(int l, int r) {
	if (r + 1 == l) return true;
	if (l == 1 && r == n) return true;
	return false;
}
 
int prev(int x) {
	if (x == 1) return n;
	return x - 1;
}
 
int next(int x) {
	if (x == n) return 1;
	return x + 1;
}
 
signed main() {
	
	ran(); fast();
 
	cin >> n >> len;
	for (int i=1; i<=n; i++) {
		cin >> pos[i];
	}
	for (int i=1; i<=n; i++) {
		cin >> by[i];
	}
	
	if (n == 1) {
		if (min(pos[1], len - pos[1]) <= by[1]) cout << 1 << endl;
		else cout << 0 << endl;
		return 0;
	}
	
	for (int i=1; i<=n; i++) {
		for (int j=1; j<=n; j++) {
			for (int f=0; f<2; f++) {
				for (int g=0; g<=n; g++) {
					dp[i][j][f][g] = LLONG_MAX;
				}
			}
		}
	}
	
	proc.push({pos[1], {{1, 1}, {0, pos[1] <= by[1]}}});
	proc.push({len-pos[n], {{n, n}, {1, (len - pos[n]) <= by[n]}}});
	
	dp[1][1][0][pos[1] <= by[1]] = pos[1];
	dp[n][n][1][(len - pos[n]) <= by[n]] = len - pos[n];
	int lr = 0;
	
	for (int isi=0; isi<=n; isi++) {
		for (int l=1; l<=n; l++) {
			int r = prev(((l - 1 + isi) % n) + 1);
			for (int f=0; f<2; f++) {
				for (int taken=0; taken<=n; taken++) {
					
					if (dp[l][r][f][taken] == LLONG_MAX) continue;
					
					int mtime = dp[l][r][f][taken];
					lr = max(lr, taken);
					
					int at = (f == 0 ? pos[l] : pos[r]);
					
					if (can(l, r)) continue;
					{
						int before = prev(l);
						int dist = abs(at - pos[before]);
						int will = min(dist, len - dist) + mtime;
						int ntaken = taken + (will <= by[before]);
						dp[before][r][0][ntaken] = min(will, dp[before][r][0][ntaken]);
					}
					
					{
						int after = next(r);
						int dist = abs(at - pos[after]);
						int will = min(dist, len - dist) + mtime;
						int ntaken = taken + (will <= by[after]);
						dp[l][after][1][ntaken] = min(will, dp[l][after][1][ntaken]);
					}
					
				}
			}
		}
	}
	
	cout << lr << endl;
	
 
}

Compilation message (stderr)

ho_t3.cpp: In function 'void usaco()':
ho_t3.cpp:15:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |  freopen("problem.in", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
ho_t3.cpp:16:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |  freopen("problem.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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