Submission #589202

#	Time	Username	Problem	Language	Result	Execution time	Memory
589202		xynex	Watching (JOI13_watching)	C++17	100 / 100	165 ms	16096 KiB

watching

/**
  * Author: Tenjin
  * Created: 28.06.2022 14:48
  * Why am I so stupid? :c
  * Slishkom slab
**/

#include <bits/stdc++.h>
// #pragma GCC optimize("inline")
// #pragma GCC optimize("-fgcse,-fgcse-lm")
// #pragma GCC optimize("-ftree-pre,-ftree-vrp")
// #pragma GCC optimize("-ffast-math")
// #pragma GCC optimize("-fipa-sra")
// #pragma GCC optimize("-fpeephole2")
// #pragma GCC optimize("-fsched-spec")
// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
// #pragma GCC optimize("unroll-loops")

using namespace std;

#define ll long long
#define dl double long
#define ull unsigned long long
#define pr pair
#define vt vector
#define ff first
#define ss second
#define mp make_pair
#define sz(a) (int)a.size()
#define pb push_back
#define pf push_front
#define popB pop_back
#define popF pop_front
#define bit_count __builtin_popcount
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sp(x) fixed << setprecision(x)

template<typename T> T get_rand(T l, T r) {
  random_device rd;
  mt19937 gen(rd());
  return uniform_int_distribution<T>(l, r)(gen);
}
template<typename T> T lcm(T a, T b) { return a * (b / __gcd(a, b)); }

template<class A> void read(vt<A>& v);
template<class A, size_t S> void read(array<A, S>& a);
template<class T> void read(T& x) { cin >> x; }
void read(double& d) { string t; read(t); d = stod(t); }
void read(long double& d) { string t; read(t); d = stold(t); }
template<class H, class... T> void read(H& h, T&... t) { read(h); read(t...); }
template<class A> void read(vt<A>& x) { for (auto& a : x) read(a); }
template<class A, size_t S> void read(array<A, S>& x) { for (auto& a : x) read(a); }

string to_string(char c) { return string(1, c); }
string to_string(bool b) { return b ? "true" : "false"; }
string to_string(const char* s) { return string(s); }
string to_string(string s) { return s; }
string to_string(vt<bool> v) { string res; for (int i = 0; i < sz(v); ++i) res += char('0' + v[i]); return res; }
template<size_t S> string to_string(bitset<S> b) { string res; for (int i = 0; i < S; ++i) res += char('0' + b[i]); return res; }
template<class T> string to_string(T v) { bool f = 1; string res; for (auto x : v) { if (!f) res += ' '; f = 0; res += to_string(x); } return res; }

template<class A> void write(A x) { cout << to_string(x); }
template<class H, class... T> void write(const H& h, const T&... t) { write(h); write(t...); }

void print() { write("\n"); }
template<class H, class... T> void print(const H& h, const T&... t) { write(h); if (sizeof...(t)) write(' '); print(t...); }

void freop(string s) {
  freopen((s + ".in").c_str(), "r", stdin);
  freopen((s + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int N = 3e4 + 1;
const ll INF = 9e18;
const int M = 2e3 + 5;
const dl pi = acos(-1);
const dl eps = 1e-12;
const int sq = 700;

int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};
/* ll vs int*/

int a[N];
int dp[M][M];
void solve() {
  int n, P, Q; read(n, P, Q);
  P = min(P, n);
  for(int i = 1; i <= n; ++i) {
    read(a[i]);
  }
  sort(a + 1, a + n + 1);
  int l = 1, r = MOD;
  while((r - l) >= 0) {
    int mid = (r + l) >> 1;
    int cnt = 0;
    for(int i = 1; i <= n; ++i) {
      int pl = 0, pr = n;
      while((pr - pl) >= 0) {
        int pmid = (pr + pl) >> 1;
        if(a[pmid] >= (a[i] - mid * 2 + 1)) pr = pmid - 1;
        else pl = pmid + 1;
      }
      pr++;
      pl--;
      pl = max(pl, 0);
      pr = min(pr, n);
      int pl1 = 0, pr1 = n;
      while((pr1 - pl1) >= 0) {
        int pmid = (pr1 + pl1) >> 1;
        if(a[pmid] >= (a[i] - mid + 1)) pr1 = pmid - 1;
        else pl1 = pmid + 1;
      }
      pr1++;
      pl1--;
      pl1 = max(pl1, 0);
      pr1 = min(pr1, n);
      for(int j = 0; j <= P; ++j) {
        dp[i][j] = (dp[pl][j] + 1);
        if(j) {
          dp[i][j] = min(dp[i][j], dp[pl1][j - 1]);
        }
      }
     // print(pr1, pr);
    }
    //print(mid, dp[n][P]);
    if(dp[n][P] <= Q) r = mid - 1;
    else l = mid + 1;
  }
  print(r + 1);
}

int main() {
  //freop("");
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
//  read(t);
  for (int i = 1; i <= t; ++i) {
    //write("Case #" + to_string(i) + ": ");
    solve();
  }
  return 0;
}

Compilation message (stderr)

watching.cpp: In function 'void solve()':
watching.cpp:99:9: warning: unused variable 'cnt' [-Wunused-variable]
   99 |     int cnt = 0;
      |         ^~~
watching.cpp: In function 'void freop(std::string)':
watching.cpp:71:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |   freopen((s + ".in").c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:72:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |   freopen((s + ".out").c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50