Submission #1019238

#	Time	Username	Problem	Language	Result	Execution time	Memory
1019238		Nurislam	Let's Win the Election (JOI22_ho_t3)	C++17	100 / 100	1881 ms	4444 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds; 
  
#define pb push_back
#define ff first
#define ss second
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>  
#define int long long
#define double long double
const int N = 1e6+5, inf = 1e9, mod = 1e9+7;
template <class F, class _S>
bool chmin(F &u, const _S &v){
	bool flag = false;
	if ( u > v ){
		u = v; flag |= true;
	}
	return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
	bool flag = false;
	if ( u < v ){
		u = v; flag |= true;
	}
	return flag;
}
double dp[505][505];
void solve(){
	int n, k;cin >> n >> k;
	vector<pair<int,int> > v;
	for(int i = 0; i < n; i++){
		int a, b;
		cin >> a >> b;
		if(b == -1)b = inf;
		v.pb({b, a});
	}
	sort(all(v));
	vector<int> a(n+1), b(n+1);
	for(int i = 1; i <= n; i++){
		b[i] = v[i-1].ff;
		a[i] = v[i-1].ss;
	}
	vector<int> _a;
	for(int i = 1; i <= n; i++)_a.pb(a[i]);
	sort(all(_a));
	double ans = 0;
	for(int i = 0; i < k; i++)ans+=_a[i];
	for(int m = 1; m <= k; m++){
		for(int i = 0; i <= n; i++)
			for(int j = 0; j <= n; j++)dp[i][j] = inf;
		dp[0][0] = 0;
		for(int i = 1; i <= k; i++){
			for(int j = 0; j <= min(i, m); j++){
				if(j && b[i] < inf)chmin(dp[i][j], dp[i-1][j-1] + (double)b[i]/(double)(j));
				chmin(dp[i][j], dp[i-1][j] + (double)a[i]/(double)(m+1));
				if(j==m){
                    vector<int> v;
                    for(int q = i+1;q <= n; q++)v.pb(a[q]);
                    sort(all(v));
 
                    int sum = 0;
                    for(int q = 0; q < k-i; q++)sum += v[q];
                    chmin(ans, dp[i][j] + (double)sum / (double)(m+1));
                }
			}
		}
	}
	cout << fixed << setprecision(15) << ans << '\n';
}
signed main(){
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int tt = 1;
	//cin >> tt;
	while(tt--){
		solve();
	}
}
 
 
 
 
 
 
 
 
 
 
 
 
 

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 12 / 12
• Subtask 5: 33 / 33
• Subtask 6: 11 / 11
• Subtask 7: 23 / 23