Submission #171102

#	Time	Username	Problem	Language	Result	Execution time	Memory
171102		ZwariowanyMarcin	Watching (JOI13_watching)	C++14	100 / 100	95 ms	8696 KiB

watching

#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define ss(x) (int) x.size()
#define pb push_back
#define ll long long
#define cat(x) cerr << #x << " = " << x << endl
#define FOR(i, n) for(int i = 0; i < n; ++i)

using namespace std;

const int nax = 2005;

int n;
int p, q;
int a[nax];
int dp[nax][nax];
int go[nax][2];

bool ok(int x) {
	if(n <= p + q) return 1;
	
	for(int i = 1; i <= n; ++i) {
		go[i][0] = upper_bound(a + 1, a + n + 1, a[i] + x - 1) - a - 1;
		go[i][1] = upper_bound(a + 1, a + n + 1, a[i] + x + x - 1) - a - 1;
	}
	for(int i = 0; i <= p; ++i)
		for(int j = 0; j <= q; ++j)
			dp[i][j] = 0;
	
	dp[0][0] = 0;
	for(int i = 0; i <= p; ++i)
		for(int j = 0; j <= q; ++j) {
			if(dp[i][j] == n) return 1;
			dp[i + 1][j] = max(dp[i + 1][j], go[dp[i][j] + 1][0]);
			dp[i][j + 1] = max(dp[i][j + 1], go[dp[i][j] + 1][1]);
		}
	return 0;
}			
	

int main() {
	scanf("%d %d %d", &n, &p, &q);
	for(int i = 1; i <= n; ++i)
		scanf("%d", a + i);
	sort(a + 1, a + n + 1);
	int l = 1;
	int r = 1000000001;
	while(l < r) {
		int m = (l + r) / 2;
		if(ok(m))
			r = m;
		else
			l = m + 1;
	}
	printf("%d", l);
	
	return 0;
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:44:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d", &n, &p, &q);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:46:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", a + i);
   ~~~~~^~~~~~~~~~~~~

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