| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 879645 | mychecksedad | Let's Win the Election (JOI22_ho_t3) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
const int N = 1e3+100, M = 1e5+10, K = 52, MX = 30;
int n, k, sum[N][N];
array<int, 2> a[N];
pair<int, double> dp[N][N];
double get(int x, double y, double j){
return y + x/j;
}
void solve(){
cin >> n >> k;
for(int i = 1; i <= n; ++i){
cin >> a[i][1] >> a[i][0];
if(a[i][0] == -1) a[i][0] = MOD;
}
sort(a+1, a+1+n);
for(int j = 0; j <= n; ++j) dp[n+1][j] = 0;
for(int i = n; i >= 1; --i){
for(int j = 0; j < n - i + 1; ++j){
sum[i][j] = min(sum[i + 1][j], j == 0 ? MOD : sum[i + 1][j - 1] + a[i][1]);
}
sum[i][n - i + 1] = sum[i + 1][n - i] + a[i][1];
}
double ans = sum[1][k];
for(int i = 0; i <= n; ++i) for(int j = 0; j <= n; ++j) dp[i][j] = {MOD, MOD};
dp[0][0] = {0, 0};
for(int i = 1; i <= k; ++i){
dp[i][0] = dp[i - 1][0];
dp[i][0].first += a[i][1];
for(int j = 1; j <= i; ++j){
double val1 = get(dp[i - 1][j].first + a[i][1], dp[i - 1][j].second, j + 1);
double val2 = get(dp[i - 1][j - 1].first, dp[i - 1][j - 1].second + a[i][0] / (double) j, j + 1);
if(val1 <= val2){
dp[i][j] = {dp[i - 1][j].first + a[i][1], dp[i - 1][j].second};
}else{
dp[i][j] = {dp[i - 1][j - 1].first, dp[i - 1][j - 1].second + a[i][0] / (double) j};
}
ans = min(ans, get(sum[i + 1][k - i] + dp[i][j].first, dp[i][j].second, j + 1));
}
}
cout << fixed << setprecision(5);
cout << ans;
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int tt = 1, aa;
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
while(tt--){
solve();
en;
}
cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
return 0;
}