Submission #467891

# Submission time Handle Problem Language Result Execution time Memory
467891 2021-08-25T13:41:16 Z kaxzert Mobile (BOI12_mobile) C++17
0 / 100
127 ms 3812 KB
/**
      00  00      11      00  00  111111  00000  111111  000000
      00 00      1111      0000      11   00     11  11  000000
      0000      11  11      00      11    00000  111111    00
      00 00    11111111    0000    11     00     11 11     00
      00  00  11      11  00  00  111111  00000  11  11    00
**/

#include<bits/stdc++.h>

using namespace std;

void setIO(string s) {
    freopen((s+".inp").c_str(),"r",stdin);
    freopen((s+".out").c_str(),"w",stdout);
}

void setIOusaco(string s) {
    freopen((s+".in").c_str(),"r",stdin);
    freopen((s+".out").c_str(),"w",stdout);
}

#define fto(i, a, b) for(int i = a; i <= b; ++i)
#define fdto(i, a, b) for(int i = a; i >= b; --i)
#define bugarr(a, i, j) cout << #a << "{" << i << "..." << j << "}:"; fto(k, i, j-1) cout << a[k] << ", "; cout << a[j] << endl;
#define ll long long
#define db double
#define ldb long double
#define ii pair<int, int>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define vt vector
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define trav(i, a) for(auto &i : a)
#define sz(a) (int)a.size()
#define fast ios::sync_with_stdio(false); cin.tie(0)

template<typename T, typename V>
bool ckmin(T &a, V b) {return (b < a)? a = b, true : false;}
template<typename T, typename V>
bool ckmax(T &a, V b) {return (b > a)? a = b, true : false;}

#define eps 0.000000000001

db cal(db mid, db height) {
    return sqrt(mid*mid - height*height);
}

#define maxN 100008

pair<db, db> a[maxN];

int main() {

    fast;
    int n;
    db mx;
    cin >> n >> mx;
    fto(i, 1, n) {
        cin >> a[i].ff >> a[i].ss;
        a[i].ss = abs(a[i].ss);
    }

    auto check = [=](db mid) -> bool {
        int pos = 0;
        db far = 0;
        fto(i, 1, n) {
            if (mid - eps > a[i].ss) {
                db dis = cal(mid, a[i].ss);
                if (a[i].ff-dis < -eps && ckmax(far, a[i].ff+dis)) {
                    pos = i;
                }
            }
        }
        if (pos == 0) return 0;
        far = a[pos].ff + cal(mid, a[pos].ss);
        fto(i, pos+1, n) {
            db dis = cal(mid, a[i].ss);
            if (far - eps > a[i].ff+dis || a[i].ff - dis - eps > far) continue;
            far = a[i].ff + dis;
        }

        return (far - eps > mx);
    };

    db left = 1, right = mx;
    db ans;
    while(right-left > 1e-6) {
        db mid = (left+right)/2;
        if (check(mid)) {
            ans = mid;
            right = mid;
        } else left = mid;
    }

    cout << fixed << setprecision(3) << ans << '\n';

    return 0;
}

Compilation message

mobile.cpp: In function 'void setIO(std::string)':
mobile.cpp:14:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |     freopen((s+".inp").c_str(),"r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen((s+".out").c_str(),"w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp: In function 'void setIOusaco(std::string)':
mobile.cpp:19:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |     freopen((s+".in").c_str(),"r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:20:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     freopen((s+".out").c_str(),"w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 204 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 204 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 332 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Incorrect 4 ms 332 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Incorrect 4 ms 332 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 5 ms 332 KB Output is correct
2 Correct 5 ms 460 KB Output is correct
3 Correct 4 ms 332 KB Output is correct
4 Incorrect 5 ms 456 KB Output isn't correct
5 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Incorrect 78 ms 1592 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Incorrect 58 ms 1604 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 61 ms 1780 KB Output is correct
2 Correct 70 ms 1644 KB Output is correct
3 Correct 60 ms 1712 KB Output is correct
4 Incorrect 118 ms 1872 KB Output isn't correct
5 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 89 ms 1988 KB Output is correct
2 Correct 84 ms 1984 KB Output is correct
3 Correct 64 ms 1980 KB Output is correct
4 Incorrect 108 ms 1952 KB Output isn't correct
5 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 95 ms 1936 KB Output is correct
2 Correct 83 ms 1924 KB Output is correct
3 Correct 63 ms 1900 KB Output is correct
4 Incorrect 127 ms 1988 KB Output isn't correct
5 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 49 ms 3812 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 66 ms 3716 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 51 ms 3656 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 65 ms 3672 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 49 ms 3628 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 67 ms 3732 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 51 ms 3656 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 66 ms 3704 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 49 ms 3652 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Runtime error 65 ms 3624 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -