Submission #3457165

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Source Code Expand

// template version 1.3
// {{{ define basic macro
using namespace std;
#include <iostream>
#include <bits/stdc++.h>
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define _rrep(i,n) rrepi(i,0,n)
#define rrepi(i,a,b) for(int i=(int)(b-1);i>=(int)(a);--i)
#define rrep(...) _overload3(__VA_ARGS__,rrepi,_rrep,)(__VA_ARGS__)
#define all(x) (x).begin(),(x).end()
#define sum(v) accumulate(all(v), 0LL)
#define sz(x) ((int)(x).size())
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
#define uni(x) sort(all(x));x.erase(unique(all(x)),x.end())
#define ten(n) ((int)1e##n)
template<class T, size_t N> size_t sza(const T (&array)[N]) { return N; }
template<class T> inline void chmax(T &a, const T &b) { if(a < b) a = b; }
template<class T> inline void chmin(T &a, const T &b) { if(a > b) a = b; }
template<class T=int> T in() {T x; cin>>x; return (x);}

struct Fast {
  Fast(){
    std::cin.tie(0);
    ios::sync_with_stdio(false);
  }
} fast;

// dump macro
#ifdef PCM
  #include "dump.hpp"
#else
  #define dump(...) 42
  #define dump_1d(...) 42
  #define dump_2d(...) 42
#endif

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef long double ld;
typedef pair<int,int> pii;
typedef tuple<int,int,int> iii;
template<typename T> using PQ = priority_queue<T, vector<T>, greater<T>>;
int dx[]={1, -1, 0, 0};
int dy[]={0, 0, 1, -1};
#define fi first
#define se second

// }}}
// varible setting{{{

#define infile "../test/sample-1.in"
#define int long long
#define INF 1000000000000000000LL
// #define INF 2147483647
#define MOD 1000000007LL

// }}}

int w[1005];
int p[1005];
int n,k;
int W;

bool isright(int x){
  double y[n];
  rep(i, n){
    y[i] = w[i]*(p[i]-x);
  }
  sort(y, y+n);
  reverse(y, y+n);

  double sum = 0;
  rep(i, k){
    sum += y[i];
  }
  if (sum>=0) return false;
  else return true;

}

int solve(){
  cin>>n>>k;
  rep(i, n){
    cin>>w[i]>>p[i];
  }
  W = accumulate(w, w+n, 0LL);

  double left = 0;
  double right = 101;
  rep(i, 100){
    int mid = (right+left)/2;
    if (isright(mid)) { right = mid;}
    else{ left = mid; }
  }
  printf("%.9f", left);

  return 0;
}

signed main() { //{{{
#ifdef INPUT_FROM_FILE
  std::ifstream in(infile);
  std::cin.rdbuf(in.rdbuf());
#endif
  solve();
  return 0;
} //}}}

Submission Info

Judge Result