Submission #307351

#	Time	Username	Problem	Language	Result	Execution time	Memory
307351		limabeans	Watching (JOI13_watching)	C++17	50 / 100	100 ms	2000 KiB

watching

#include <bits/stdc++.h>
using namespace std;

template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl





using ll = long long;


const int maxn = 1e6 + 5;


int n, small, large;
int a[maxn];

map<vector<int>, bool> dp;





bool solve(int w, int i, int j, int k) {
    if (j>small) return false;
    if (k>large) return false;
    if (i==n) return true;
    vector<int> key = {i,j,k};
    if (dp.count(key)) return dp[key];
    bool &res = dp[key] = false;


    
    // use small
    {
	int to = lower_bound(a,a+n,a[i]+w)-a;
	res |= solve(w, to, j+1, k);
    }

    // use large
    {
	int to = lower_bound(a,a+n,a[i]+2*w)-a;
	res |= solve(w, to, j, k+1);
    }


    return res;
}



bool test(int w) {
    dp.clear();
    return solve(w, 0, 0, 0);
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);  cout.tie(0);

    cin>>n>>small>>large;
    assert(n<=100);
    if (small>=n || large>=n) out(1);

    
    for (int i=0; i<n; i++) {
	cin>>a[i];
    }

    sort(a,a+n);

    int lo=0;
    int hi=(int)1e9 + 20;
    while (hi-lo>1) {
	int mid=(lo+hi)/2;

	if (test(mid)) {
	    hi = mid;
	} else {
	    lo = mid;
	}
    }

    cout<<hi<<endl;
    
    return 0;
}

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