Submission #36399

#	Time	Username	Problem	Language	Result	Execution time	Memory
36399		Weak123456	Watching (JOI13_watching)	C++14	100 / 100	83 ms	17932 KiB

watching

#include <bits/stdc++.h>
#define ii pair <int, int>
#define x first
#define y second
#define db(x) cerr << #x << " = " << x << endl;

using namespace std;

inline void read(int &x){register int c = getchar();x = 0; int neg = 0;for (;((c<48 || c>57) && c != '-') ;c = getchar());if(c=='-') {neg=1;c=getchar();}for(;c>47 && c<58;c = getchar()) {x = (x<<1) + (x<<3) + c - 48;}if(neg) x=-x;}
inline void read(long long &x){register int c = getchar();x = 0; int neg = 0;for (;((c<48 || c>57) && c != '-') ;c = getchar());if(c=='-') {neg=1;c=getchar();}for(;c>47 && c<58;c = getchar()) {x = (x<<1) + (x<<3) + c - 48;}if(neg) x=-x;}
inline void writeln(long long x){char buffor[21];register int i=0;int neg=0; if (x<0) {neg=1; x= -x;}do{buffor[i++]=(x%10)+'0';x/=10;} while(x);i--;if (neg) putchar('-');while(i>=0) putchar(buffor[i--]);putchar('\n');}
inline void write(long long x){char buffor[21];register int i=0;int neg=0; if (x<0) {neg=1; x= -x;}do{buffor[i++]=(x%10)+'0';x/=10;} while(x);i--;if (neg) putchar('-');while(i>=0) putchar(buffor[i--]);putchar(' ');}

const int N = 2007;

int n, p, q;
int a[N];
int f[N][N];
ii nxt[N];

inline int BS(int i, long long d){
	int l = i;
	int r = n;
	while (l <= r){
		int mid = (l + r) / 2;
		if (a[mid] - a[i] + 1 <= d)
			l = mid + 1;
		else
			r = mid - 1;
	}
	return r;
}

bool check(int x){
	for (int i = 1; i <= n; i++){
		nxt[i].x = BS(i, x);
		nxt[i].y = BS(i, 2 * x);
	}
	for (int i = 0; i <= p; i++)
		for (int j = 0; j <= q; j++){
			f[i][j] = 0;
			if (j) f[i][j] = max(f[i][j], nxt[f[i][j - 1] + 1].y);
			if (i) f[i][j] = max(f[i][j], nxt[f[i - 1][j] + 1].x);
			if (f[i][j] >= n) return true;
		}
	return false;
}	

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	read(n); read(p); read(q);
	p = min(p, n); q = min(q, n);
	for (int i = 1; i <= n; i++)
		read(a[i]);
	sort(a + 1, a + n + 1);
	int l = 1;
	int r = 1000000000;
	while (l <= r){
		int mid = (l + r) / 2;
		if (check(mid)) 
			r = mid - 1;
		else
			l = mid + 1;
	}
	writeln(l);
}

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