oj.uz

Submission #151251

# Submission time Handle Problem Language Result Execution time Memory
151251 2019-09-02T10:30:15 Z TadijaSebez Watching (JOI13_watching) C++11
100 / 100
 206 ms 16572 KB 
#include <bits/stdc++.h>
using namespace std;
const int N=2050;
const int inf=1e9+7;
int n,p,q;
int dp[N][N],a[N];
void Clear(){ for(int i=0;i<=n;i++) for(int j=0;j<=n;j++) dp[i][j]=inf;}
void ckmn(int &a, int b){ a=min(a,b);}
bool Check(int w)
{
	int ptr=0,qtr=0;
	Clear();
	dp[0][0]=0;
	for(int i=1;i<=n;i++)
	{
		while(a[i]-a[ptr+1]>=w) ptr++;
		while(a[i]-a[qtr+1]>=2*w) qtr++;
		for(int j=0;j<=i;j++)
		{
			dp[i][j]=dp[ptr][j]+1;
			if(j) ckmn(dp[i][j],dp[qtr][j-1]);
		}
	}
	for(int j=0;j<=min(n,q);j++) if(dp[n][j]<=p) return 1;
	return 0;
}
int main()
{
	scanf("%i %i %i",&n,&p,&q);
	for(int i=1;i<=n;i++) scanf("%i",&a[i]);
	sort(a+1,a+1+n);
	int top=a[n]-a[1]+1,bot=1,mid,ans;
	while(top>=bot)
	{
		mid=top+bot>>1;
		if(Check(mid)) ans=mid,top=mid-1;
		else bot=mid+1;
	}
	printf("%i\n",ans);
	return 0;
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:35:10: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   mid=top+bot>>1;
       ~~~^~~~
watching.cpp:29:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i %i %i",&n,&p,&q);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~
watching.cpp:30:29: 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("%i",&a[i]);
                        ~~~~~^~~~~~~~~~~~

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 1016 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 3 ms 912 KB Output is correct
5 Correct 3 ms 1016 KB Output is correct
6 Correct 3 ms 916 KB Output is correct
7 Correct 3 ms 916 KB Output is correct
8 Correct 3 ms 988 KB Output is correct
9 Correct 3 ms 888 KB Output is correct
10 Correct 3 ms 876 KB Output is correct
11 Correct 3 ms 884 KB Output is correct
12 Correct 3 ms 888 KB Output is correct
13 Correct 3 ms 884 KB Output is correct
14 Correct 3 ms 892 KB Output is correct
15 Correct 3 ms 1016 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 186 ms 16572 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 192 ms 16448 KB Output is correct
4 Correct 196 ms 16444 KB Output is correct
5 Correct 196 ms 16452 KB Output is correct
6 Correct 198 ms 16452 KB Output is correct
7 Correct 185 ms 16448 KB Output is correct
8 Correct 193 ms 16440 KB Output is correct
9 Correct 199 ms 16448 KB Output is correct
10 Correct 201 ms 16452 KB Output is correct
11 Correct 206 ms 16444 KB Output is correct
12 Correct 204 ms 16452 KB Output is correct
13 Correct 154 ms 16380 KB Output is correct
14 Correct 166 ms 16452 KB Output is correct
15 Correct 174 ms 16440 KB Output is correct