Submission #419508

#	Time	Username	Problem	Language	Result	Execution time	Memory
419508		amunduzbaev	Watching (JOI13_watching)	C++14	50 / 100	133 ms	28100 KiB

watching

/* made by amunduzbaev */
 
//~ #include <ext/pb_ds/assoc_container.hpp>
//~ #include <ext/pb_ds/tree_policy.hpp>
#include "bits/stdc++.h"
 
using namespace std;
//~ using namespace __gnu_pbds;

#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define NeedForSpeed ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define vv vector
#define mem(arr, v) memset(arr, v, sizeof arr)
#define int long long
 
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii; 
typedef vector<int> vii;
typedef vector<pii> vpii;
template<class T> bool umin(T& a, const T& b) { return a > b ? a = b, true : false; }
template<class T> bool umax(T& a, const T& b) { return a < b ? a = b, true : false; }
template<int sz> using tut = array<int, sz>;
void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);  
	freopen((s+".out").c_str(),"w",stdout); NeedForSpeed }
//~ template<class T> using oset = tree<T, 
//~ null_type, less_equal<T>, rb_tree_tag, 
//~ tree_order_statistics_node_update>;
 
const int N = 305;
const int mod = 1e9+7;
const ll inf = 1e18;
const ld Pi = acos(-1);
 
#define MULTI 0
int n, m, k, s, t, q, ans, res, a[N];
bool dp[N][N][N];

bool check(int w){
	mem(dp, 0);
	int l = 1, r = 1;
	for(int i=0;i<=n;i++) dp[0][0][i] = dp[0][i][0] = 1;
	for(int i=1;i<=n;i++){
		while(a[i] - a[l] + 1 > 2 * w) l++;
		while(a[i] - a[r] + 1 > w) r++;
		for(int j=0;j<=q;j++){
			for(int t=0;t<=m;t++){
				if(j) dp[i][j][t] |= dp[l-1][j-1][t];
				if(t) dp[i][j][t] |= dp[r-1][j][t-1];
			}
		}
	}
	
	//~ cout<<w<<"\n";
	//~ for(int i=0;i<=n;i++){
		//~ for(int j=0;j<=q;j++){
			//~ for(int l=0;l<=m;l++){
				//~ cout<<dp[i][j][l]<<" ";
			//~ } cout<<"\n";
		//~ } cout<<"\n";
	//~ } cout<<"\n";
	
	for(int i=1;i<=q;i++){
		for(int j=1;j<=m;j++) if(dp[n][i][j]) return 1;
	} return 0;
}

void solve(int t_case){
	cin>>n>>m>>q;
	for(int i=1;i<=n;i++) cin>>a[i];
	if(m + q > n) { cout<<1<<"\n"; return; }
	sort(a+1, a+n+1);
	a[0] = a[1];
	//~ check(4);
	
	int l = 1, r = mod;
	while(l + 1 < r){
		int m = (l + r)>>1;
		if(check(m)) r = m;
		else l = m;
	} if(!check(l)) l = r;
	cout<<l<<"\n";
}

signed main(){
	NeedForSpeed
	if(MULTI){
		int t; cin>>t;
		for(int t_case = 1; t_case <= t; t_case++) solve(t_case);
	} else solve(1);
	return 0;
}

Compilation message (stderr)

watching.cpp: In function 'void usaco(std::string)':
watching.cpp:32:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 | void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:33:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |  freopen((s+".out").c_str(),"w",stdout); NeedForSpeed }
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 50 / 50
• Subtask 2: 0 / 50