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Submission #199178

# Submission time Handle Problem Language Result Execution time Memory
199178 2020-01-29T22:56:49 Z imaxblue Mobile (BOI12_mobile) C++17
0 / 100
 402 ms 28860 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define mp make_pair
#define pb push_back
#define x first
#define y second
#define pii pair<int, int>
#define p3i pair<pii, int>
#define pll pair<ll, ll>
#define p3l pair<pll, ll>
#define vi vector<int>
#define vpii vector<pii>
#define vp3i vector<p3i>
#define vpll vector<pll>
#define vp3l vector<p3l>
#define lseg L, (L+R)/2, N*2+1
#define rseg (L+R)/2+1, R, N*2+2
#define ub upper_bound
#define lb lower_bound
#define pq priority_queue
#define MN 1000000007
#define fox(k, x) for (int k=0; k<x; ++k)
#define fox1(k, x) for (int k=1; k<=x; ++k)
#define foxr(k, x) for (int k=x-1; k>=0; --k)
#define fox1r(k, x) for (int k=x; k>0; --k)
#define ms multiset
#define flood(x) memset(x, 0x3f3f3f3f, sizeof x)
#define drain(x) memset(x, 0, sizeof x)
#define rng() ((rand() << 14)+rand())
#define scan(X) do{while((X=getchar())<'0'); for(X-='0'; '0'<=(_=getchar()); X=(X<<3)+(X<<1)+_-'0');}while(0)
char _;
#define pi 3.14159265358979323846
#define startrng mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

double ans;
int n, d, x, y;
vector<pll> v;
vector<pll> hull;
//f(x) = x^2 + mx + b
//xa1+b1=xa2+b2
//x=(b2-b1)/(a1-a2);
double eval(pll A, double X){
  //cout << A.x << ' ' << A.y << ' ' << X << endl;
  return sqrt(X*X+X*A.y+A.x);
}
void check(pll A, pll B){
  double x=(B.x-A.x)/double(A.y-B.y);
  if (x<0 || x>d) return;
  ans = max(eval(A, x), ans);
}
bool cross(pll A, pll O, pll B){
  return (A.x-O.x)*(B.y-O.y)-(A.y-O.y)*(B.x-O.x)<=0;
}
int32_t main(){
  scanf("%i%i", &n, &d);
  fox(l, n){
    scanf("%i%i", &x, &y);
    v.pb(mp(x, y));
  }
  sort(v.begin(), v.end());
  for (auto i:v){
    while(hull.size()>1 && cross(hull[hull.size()-2], hull.back(), i)){
      hull.pop_back();
    }
    hull.pb(mp(i.y*i.y+i.x*i.x, -2*i.x));
  }
  fox(l, hull.size()-1){
    check(hull[l], hull[l+1]);
  }
  //cout << ans << endl;
  double lft=(1LL<<60), rit=(1LL<<60);
  fox(l, hull.size()){
    lft=min(lft, eval(hull[l], 0));
    rit=min(rit, eval(hull[l], d));
  }
  //cout << lft << ' ' << rit << endl;
  ans = max(ans, max(lft, rit));
  //cout << sqrt(ans) << endl;
  printf("%.8lf", ans);
  return 0;
}

Compilation message

mobile.cpp: In function 'int32_t main()':
mobile.cpp:23:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define fox(k, x) for (int k=0; k<x; ++k)
mobile.cpp:68:7:
   fox(l, hull.size()-1){
       ~~~~~~~~~~~~~~~~            
mobile.cpp:68:3: note: in expansion of macro 'fox'
   fox(l, hull.size()-1){
   ^~~
mobile.cpp:23:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define fox(k, x) for (int k=0; k<x; ++k)
mobile.cpp:73:7:
   fox(l, hull.size()){
       ~~~~~~~~~~~~~~              
mobile.cpp:73:3: note: in expansion of macro 'fox'
   fox(l, hull.size()){
   ^~~
mobile.cpp:56:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%i%i", &n, &d);
   ~~~~~^~~~~~~~~~~~~~~~
mobile.cpp:58:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%i%i", &x, &y);
     ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 376 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 256 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 504 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 7 ms 632 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 504 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 508 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #7
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 30 ms 2552 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #8
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 28 ms 2540 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 2536 KB Output is correct
2 Correct 33 ms 2540 KB Output is correct
3 Correct 30 ms 3428 KB Output is correct
4 Incorrect 44 ms 2540 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #10
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 39 ms 2660 KB Output is correct
2 Correct 39 ms 2540 KB Output is correct
3 Correct 31 ms 2536 KB Output is correct
4 Incorrect 44 ms 2516 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #11
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 39 ms 3556 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #12
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 139 ms 8844 KB Output is correct
2 Correct 166 ms 8668 KB Output is correct
3 Correct 170 ms 8668 KB Output is correct
4 Incorrect 196 ms 8668 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #13
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 179 ms 14928 KB Output is correct
2 Incorrect 153 ms 8828 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #14
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 167 ms 16824 KB Output is correct
2 Correct 206 ms 16976 KB Output is correct
3 Correct 203 ms 16976 KB Output is correct
4 Incorrect 241 ms 17020 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #15
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 222 ms 17364 KB Output is correct
2 Incorrect 182 ms 16976 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #16
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 193 ms 16852 KB Output is correct
2 Incorrect 241 ms 16824 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #17
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 255 ms 19484 KB Output is correct
2 Incorrect 217 ms 16804 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #18
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 221 ms 16976 KB Output is correct
2 Correct 272 ms 16976 KB Output is correct
3 Correct 265 ms 16848 KB Output is correct
4 Incorrect 321 ms 16848 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #19
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 289 ms 25380 KB Output is correct
2 Incorrect 243 ms 16976 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #20
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 270 ms 16948 KB Output is correct
2 Correct 342 ms 19260 KB Output is correct
3 Correct 329 ms 16844 KB Output is correct
4 Incorrect 402 ms 16848 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #21
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 351 ms 28860 KB Output is correct
2 Incorrect 299 ms 16904 KB Output isn't correct
3 Halted 0 ms 0 KB -