Submission #116625

#	Time	Username	Problem	Language	Result	Execution time	Memory
116625		roseanne_pcy	Watching (JOI13_watching)	C++14	50 / 100	1040 ms	16376 KiB

watching

#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
using namespace std;
#define X first
#define Y second
#define pb push_back
typedef pair<int, int> ii;
typedef long long ll;

int n;

const int maxn = 2005;

int arr[maxn];

int dp[maxn][maxn];

int w;

int solve(int p, int q)
{
	if(dp[p][q] != -1) return dp[p][q];
	int ans = 0;
	if(p> 0)
	{
		int lst = solve(p-1, q);
		if(lst == n)
		{
			return dp[p][q] = n;
		}
		int rng = arr[lst+1]+w-1;
		int val = upper_bound(arr+1, arr+n+1, rng)-arr-1;
		ans = max(ans, val);
	}
	if(q> 0)
	{
		int lst = solve(p, q-1);
		if(lst == n)
		{
			return dp[p][q] = n;
		}
		int rng = arr[lst+1]+2*w-1;
		int val = upper_bound(arr+1, arr+n+1, rng)-arr-1;
		ans = max(ans, val);
	}
	return dp[p][q] = ans;
}

int main()
{
	int p, q;
	scanf("%d %d %d", &n, &p, &q);
	for(int i = 1; i<= n; i++) scanf("%d", &arr[i]);
	sort(arr+1, arr+n+1);
	n = unique(arr+1, arr+n+1)-(arr+1);
	if(p>= n || q>= n)
	{
		printf("1\n"); return 0;
	}
	int lo = 1, hi = 1e9;
	while(lo< hi)
	{
		int mid = (lo+hi)/2;
		memset(dp, -1, sizeof dp);
		w = mid;
		if(solve(p, q) == n) hi = mid;
		else lo = mid+1;
	}
	printf("%d\n", lo);
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:53:7: 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:54:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i = 1; i<= n; i++) scanf("%d", &arr[i]);
                             ~~~~~^~~~~~~~~~~~~~~

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