Submission #51435

# Submission time Handle Problem Language Result Execution time Memory
51435 2018-06-18T02:23:14 Z DrumpfTheGodEmperor Watching (JOI13_watching) C++14
100 / 100
154 ms 16380 KB
#include <bits/stdc++.h>
#define INF 1000000007
#define pb push_back
#define bw(i,r,l) for (int i=r-1;i>=l;i--)
#define fw(i,l,r) for (int i=l;i<r;i++)
using namespace std;
int n,p,q,a[2001],poss[2001],posl[2001],dp[2001][2001];
bool check(int w) {
	fw (i,0,n) {
		poss[i]=upper_bound(a,a+n,a[i]+w-1)-a;
		posl[i]=upper_bound(a,a+n,a[i]+2*w-1)-a;
	}
	memset(dp,-1,sizeof(dp));
	dp[0][0]=0; //DP[i][j] stores not the maximal place you can reach, but minimal you can't reach
	fw (i,0,p+1) fw (j,0,q+1) if (dp[i][j]!=-1) {
		if (dp[i][j]==n) return true;
		dp[i+1][j]=max(dp[i+1][j],poss[dp[i][j]]);
		dp[i][j+1]=max(dp[i][j+1],posl[dp[i][j]]);
	}
	return false;
}
int ans(int l,int r) {
	int mid=(l+r)/2;
	if (l==r) return l;
	bool temp=check(mid);
	if (temp) return ans(l,mid);
	else return ans(mid+1,r);
}
signed main() {
	//freopen("aome.inp","r",stdin);
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin>>n>>p>>q;
	fw (i,0,n) cin>>a[i]; 
	if (p+q>=n) {cout<<"1"; return 0;}
	sort(a,a+n);
	/*
	DP[i][j]: Furthest position you can reach with i small cameras and j big ones.
	Binary search for the answer, then create a board for the furthest position of each one.
	Total complexity: O(PQ * log2(1e9))
	*/
	cout<<ans(1,1000000000);
	return 0;
}
# Verdict Execution time Memory Grader output
1 Correct 46 ms 15992 KB Output is correct
2 Correct 3 ms 15992 KB Output is correct
3 Correct 95 ms 16088 KB Output is correct
4 Correct 2 ms 16088 KB Output is correct
5 Correct 3 ms 16088 KB Output is correct
6 Correct 2 ms 16088 KB Output is correct
7 Correct 41 ms 16176 KB Output is correct
8 Correct 54 ms 16304 KB Output is correct
9 Correct 40 ms 16304 KB Output is correct
10 Correct 40 ms 16304 KB Output is correct
11 Correct 41 ms 16332 KB Output is correct
12 Correct 41 ms 16332 KB Output is correct
13 Correct 41 ms 16332 KB Output is correct
14 Correct 40 ms 16332 KB Output is correct
15 Correct 40 ms 16332 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 43 ms 16332 KB Output is correct
2 Correct 2 ms 16332 KB Output is correct
3 Correct 3 ms 16332 KB Output is correct
4 Correct 2 ms 16332 KB Output is correct
5 Correct 3 ms 16332 KB Output is correct
6 Correct 3 ms 16332 KB Output is correct
7 Correct 44 ms 16356 KB Output is correct
8 Correct 60 ms 16356 KB Output is correct
9 Correct 56 ms 16356 KB Output is correct
10 Correct 94 ms 16380 KB Output is correct
11 Correct 69 ms 16380 KB Output is correct
12 Correct 154 ms 16380 KB Output is correct
13 Correct 48 ms 16380 KB Output is correct
14 Correct 80 ms 16380 KB Output is correct
15 Correct 52 ms 16380 KB Output is correct