Submission #273061

#	Time	Username	Problem	Language	Result	Execution time	Memory
273061		jc713	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	122 ms	127480 KiB

ho_t3

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

using ll = long long;
using ld = long double;
using db = double;
using str = string;

using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;

using vi = vector<int>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;

using indexed_set = tree<pair<int, int>,null_type,less<pair<int, int>>,rb_tree_tag,
	tree_order_statistics_node_update>;

#define mp make_pair
#define f first
#define s second
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() //
#define rsz resize
#define ins insert //
#define ft front() //
#define bk back()
#define pf push_front //
#define pb push_back
#define eb emplace_back //
#define lb lower_bound //
#define ub upper_bound //

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5; //
const int IINF = 1e9;
const ll INF = 1e18; //
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; //
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); //
//
template<class T> bool ckmin(T& a, const T& b) { 
	return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { //
	return a < b ? a = b, 1 : 0; } //
constexpr int pct(int x) { return __builtin_popcount(x); } //
constexpr int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) //
ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down
// IGNORE
ll half(ll x) { return fdiv(x,2); }

template<class T, class U> T fstTrue(T lo, T hi, U f) {
	hi ++; assert(lo <= hi); // assuming f is increasing
	while (lo < hi) { // find first index such that f is true 
		T mid = half(lo+hi);
		f(mid) ? hi = mid : lo = mid+1; 
	} 
	return lo;
}
template<class T, class U> T lstTrue(T lo, T hi, U f) {
	lo --; assert(lo <= hi); // assuming f is decreasing
	while (lo < hi) { // find first index such that f is true 
		T mid = half(lo+hi+1);
		f(mid) ? lo = mid : hi = mid-1;
	} 
	return lo;
}
template<class T> void remDup(vector<T>& v) { 
	sort(all(v)); v.erase(unique(all(v)),end(v)); }
// IGNORE

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
 
    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);

template<class T> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }

template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }

// TO_STRING
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
str ts(bool b) { 
	#ifdef LOCAL
		return b ? "true" : "false"; 
	#else 
		return ts((int)b);
	#endif
}
template<class A> str ts(complex<A> c) { 
	stringstream ss; ss << c; return ss.str(); }
str ts(vector<bool> v) {
	str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]);
	res += "}"; return res; }
template<size_t SZ> str ts(bitset<SZ> b) {
	str res = ""; F0R(i,SZ) res += char('0'+b[i]);
	return res; }
template<class A, class B> str ts(pair<A,B> p);
template<class T> str ts(T v) { // containers with begin(), end()
	#ifdef LOCAL
		bool fst = 1; str res = "{";
		for (const auto& x: v) {
			if (!fst) res += ", ";
			fst = 0; res += ts(x);
		}
		res += "}"; return res;
	#else
		bool fst = 1; str res = "";
		for (const auto& x: v) {
			if (!fst) res += " ";
			fst = 0; res += ts(x);
		}
		return res;

	#endif
}
template<class A, class B> str ts(pair<A,B> p) {
	#ifdef LOCAL
		return "("+ts(p.f)+", "+ts(p.s)+")"; 
	#else
		return ts(p.f)+" "+ts(p.s);
	#endif
}

// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) { 
	pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) { 
	pr(h); if (sizeof...(t)) pr(" "); ps(t...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
	cerr << ts(h); if (sizeof...(t)) cerr << ", ";
	DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL, chk -> fake assert
	#define dbg(...) cerr << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
	#define chk(...) if (!(__VA_ARGS__)) cerr << "Line(" << __LINE__ << ") -> function(" \
		 << __FUNCTION__  << ") -> CHK FAILED: (" << #__VA_ARGS__ << ")" << "\n", exit(0);
#else
	#define dbg(...) 0
	#define chk(...) 0
#endif

// FILE I/O
void setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { ios_base::sync_with_stdio(0); cin.tie(0); }
void setIO(str s = "") {
	unsyncIO();
	// cin.exceptions(cin.failbit); 
	// throws exception when do smth illegal
	// ex. try to read letter into int
	if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}

/*template<class Fun>
class y_combinator_result {
	Fun fun_;
public:
	template<class T>
	explicit y_combinator_result(T &&fun): fun_(std::forward<T>(fun)) {}
 
	template<class ...Args>
	decltype(auto) operator()(Args &&...args) {
		return fun_(std::ref(*this), std::forward<Args>(args)...);
	}
};
 
template<class Fun>
decltype(auto) y_combinator(Fun &&fun) {
	return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun));
}*/

int main(){
	setIO();
	ll N, L;
	cin >> N >> L;
	vpl XT(N);
	F0R(a, N)
		cin >> XT[a].f;
	F0R(a, N)
		cin >> XT[a].s;
	vpl RXT = XT;
	F0R(a, N)
		RXT[a].f = L - RXT[a].f;
	reverse(all(RXT));
	XT.insert(XT.begin(), mp(0, INF));
	RXT.insert(RXT.begin(), mp(0, INF));
	ll dp[N + 1][N + 1][N + 1][2];//num left, num right, num stamps, left/right
	F0R(a, N + 1)
		F0R(b, N + 1)
			F0R(c, N + 1)
				fill(dp[a][b][c], dp[a][b][c] + 2, INF);
	dp[0][0][0][1] = 0;
	dp[0][0][0][0] = 0;
	int ma = 0;
	F0R(a, N + 1)
		F0R(b, N + 1){
			if(a + b > N)
				break;
			F0R(c, N + 1){
				if(c > a + b)
					break;
				if(a == 0 && b == 0)
					continue;
				if(a){
					if(dp[a - 1][b][c - 1][0] + RXT[a].f - RXT[a - 1].f <= RXT[a].s){
						dp[a][b][c][0] = min(dp[a][b][c][0], dp[a - 1][b][c - 1][0] + RXT[a].f - RXT[a - 1].f);
						if(dp[a - 1][b][c - 1][0] != INF)
							ma = max(ma, c);
					}
					if(dp[a - 1][b][c - 1][1] + RXT[a].f + XT[b].f <= RXT[a].s){
						dp[a][b][c][0] = min(dp[a][b][c][0], dp[a - 1][b][c - 1][1] + RXT[a].f + XT[b].f);
						if(dp[a - 1][b][c - 1][1] != INF)
							ma = max(ma, c);
					}
					if(dp[a - 1][b][c][0] + RXT[a].f - RXT[a - 1].f > RXT[a].s){
						dp[a][b][c][0] = min(dp[a][b][c][0], dp[a - 1][b][c][0] + RXT[a].f - RXT[a - 1].f);
						if(dp[a - 1][b][c][0] != INF)
							ma = max(ma, c);
					}
					if(dp[a - 1][b][c][1] + RXT[a].f + XT[b].f > RXT[a].s){
						dp[a][b][c][0] = min(dp[a][b][c][0], dp[a - 1][b][c][1] + RXT[a].f + XT[b].f);
						if(dp[a - 1][b][c][1] != INF)
							ma = max(ma, c);
					}
				}
				if(b){
					if(dp[a][b - 1][c - 1][0] + RXT[a].f + XT[b].f <= XT[b].s){
						dp[a][b][c][1] = min(dp[a][b][c][1], dp[a][b - 1][c - 1][0] + RXT[a].f + XT[b].f);
						if(dp[a][b - 1][c - 1][0] != INF)
							ma = max(ma, c);
					}
					if(dp[a][b - 1][c - 1][1] + XT[b].f - XT[b - 1].f <= XT[b].s){
						dp[a][b][c][1] = min(dp[a][b][c][1], dp[a][b - 1][c - 1][1] + XT[b].f - XT[b - 1].f);
						if(dp[a][b - 1][c - 1][1] != INF)
							ma = max(ma, c);
					}
					if(dp[a][b - 1][c][0] + RXT[a].f + XT[b].f > XT[b].s){
						dp[a][b][c][1] = min(dp[a][b][c][1], dp[a][b - 1][c][0] + RXT[a].f + XT[b].f);
						if(dp[a][b - 1][c][0] != INF)
							ma = max(ma, c);
					}
					if(dp[a][b - 1][c][1] + XT[b].f - XT[b - 1].f > XT[b].s){
						dp[a][b][c][1] = min(dp[a][b][c][1], dp[a][b - 1][c][1] + XT[b].f - XT[b - 1].f);
						if(dp[a][b - 1][c][1] != INF)
							ma = max(ma, c);
					}
				}
			}
		}
	cout << ma << endl;
}

Compilation message (stderr)

ho_t3.cpp: In function 'void setIn(str)':
ho_t3.cpp:188:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  188 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
ho_t3.cpp: In function 'void setOut(str)':
ho_t3.cpp:189:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  189 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

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