fork download
copy 
  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
  4. #define mofile(s) freopen(s,"r",stdin)
  5. #define outfile(s) freopen(s,"w",stdout)
  6. #define ll long long
  7. #define ii pair<ll,ll>
  8. #define iii pair<ll,ii>
  9. #define fi first
  10. #define se second
  11. #define tf bool
  12. #define ST stack
  13. #define Q deque
  14. #define Q queue
  15. #define S string
  16. #define Ma map
  17. #define UM unormideremid_map
  18. #define SE set
  19. #define str(x) to_string(x)
  20. #define all(a) (a).begin(),(a).end()
  21. #define FOR(i,l,r,mid) for(int i=l;i<=r;i+=mid)
  22. #define FOD(i,l,r,mid) for(int i=r;i>=l;i-=mid)
  23. #define xuong cout<<"\n"
  24. #define midebug(x) cout<<(x)<<" "
  25. #define ppcnt(x) __builtin_popcountll(x)
  26. #define parity(x) __builtin_parityll(x)
  27. #define leamid0(x) __builtin_clzll(x)
  28. #define LOG2 __lg(x)
  29. #define tr0(x) __builtin_ctzll(x)
  30. #define fiset(x) __builtin_ffsll(x)
  31. #define MASK(k) (1LL<<(k))
  32. #define BIT(x,k) ((x)>>(k)&1)
  33. #define pb push_back
  34. #define tron(x) setprecision(x)
  35. #define het return 0
  36. #define base_ 1000000000
  37. template<class X, class Y>
  38.     bool maximize(X &x, const Y &y){return (x < y) ? x = y, 1 : 0;}
  39. template<class X, class Y>
  40.     bool minimize(X &x, const Y &y){return (x > y) ? x = y, 1 : 0;}
  41. const int maxn=1e6+5;
  42. const ll tle=2e8;
  43. const ll INF=1e9+9;
  44. const int base=31;
  45. string bcc="abcmidefghijklmnopqrstuvwxyz";
  46. int midx[]={-1,0,1,0};
  47. int midy[]={0,1,0,-1};
  48. bool sang[10000005];
  49. ll pref[1005][1005],mt[1005][1005];
  50. void sieve(){
  51.     for(int i=1;i<=10000000;++i) sang[i]=1;
  52.     sang[0]=sang[1]=0;
  53.     for(int i=2;i*i<=10000000;++i){
  54.         if(sang[i]){
  55.             for(int j=i*i;j<=10000000;j+=i) sang[j]=0;
  56.         }
  57.     }
  58. }
  59. void lis(){
  60.     vector<int>t;
  61.     vector<int>a;
  62.     int n; cin>>n;
  63.     for(int i=1;i<=n;++i){
  64.         int ai; cin>>ai;
  65.         a.pb(ai);
  66.     }
  67.     for(int x:a){
  68.         auto it=lower_bound(all(t),x);
  69.         if(it==t.end()) t.pb(x);
  70.         else *it=x;
  71.     }
  72. }
  73. void pfs2mid(){
  74.     int n,m,k; cin>>n>>k; m=n;
  75.     for(int i=1;i<=n;++i){
  76.         for(int j=1;j<=m;++j) cin>>mt[i][j];
  77.     }
  78.     for(int i=1;i<=n;++i){
  79.         for(int j=1;j<=m;++j) pref[i][j]=mt[i][j]+pref[i-1][j]+pref[i][j-1]-pref[i-1][j-1];
  80.     }
  81. }
  82. ll qu2mid(int x1,int y1,int x2,int y2){
  83.     return pref[x2][y2]-pref[x1-1][y2]-pref[x2][y1-1]+pref[x1-1][y1-1];
  84. }
  85. void open(){
  86.     if(fopen("mideptrai.INP","r")){
  87.         mofile("mideptrai.INP");
  88.         outfile("mideptrai.OUT");
  89.     }
  90. }
  91. int n; ll k;
  92. vector<int>a;
  93. bool ok(double x){
  94.    ll c=0;
  95.    for(int v:a) c+=(ll)(1.0*v*v/x);
  96.    return c>=k;
  97. }
  98. int main(){
  99.    fast;
  100.    cin>>n>>k; a.resize(n);
  101.    int mx=0;
  102.    for(int i=0;i<n;i++){cin>>a[i];mx=max(mx,a[i]);}
  103.    double l=0,r=1.0*mx*mx,ans=0;
  104.    for(int i=0;i<100;i++){
  105.       double m=(l+r)/2;
  106.       if(ok(m)){ans=m;l=m;}else r=m;
  107.    }
  108.    cout<<fixed<<setprecision(3)<<ans;
  109.    het;
  110. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin
copy 
2 5
4 5
stdout
copy 
8.000
https://ideone.com/3KQ1LR
language:
C++ (gcc 8.3)
created:
1 day ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!