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Submission #56143

# Submission time Handle Problem Language Result Execution time Memory
56143 2018-07-10T05:53:32 Z 노영훈(#1580) Mobile (BOI12_mobile) C++11
4 / 100
 388 ms 32840 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double lf;
typedef pair<ll, ll> pll;
const int MX=1000010, inf=2e9;
const ll linf=5e18;

int n;
ll l;
pll P[MX];

ll sq(ll x){ return x*x; }

lf itst(pll a, pll b){
    lf dm=a.first-b.first, db=a.second-b.second;
    return -db/dm;
}
lf eval(pll a, lf x){
    return a.first*x + a.second + x*x;
}

int main(){
    ios::sync_with_stdio(0); cin.tie(0);
    cin>>n>>l;
    for(int i=1; i<=n; i++){
        ll x, y; cin>>x>>y;
        P[i]={-2*x,x*x+y*y};
    }
    sort(P+1, P+n+1, [](pll &a, pll &b){
        if(a.first==b.first) return a.second>b.second;
        return a.first>b.first;
    });
    // for(int i=1; i<=n; i++) cout<<P[i].first<<' '<<P[i].second<<'\n';
    vector<pll> stk; // m, b
    stk.push_back({0, linf});
    for(int i=1; i<=n; i++){
        pll now=P[i];
        while(!stk.empty()){
            pll prv=stk.back(); stk.pop_back();
            if(now.first==prv.first) continue;
            if(!stk.empty() && itst(stk.back(), prv)>=itst(prv, now)) continue;
            else { stk.push_back(prv); break; }
        }
        stk.push_back(P[i]);
    }
    lf prv=-linf, ans=0;
    for(int i=1; i<(int)stk.size(); i++){
        lf now=itst(stk[i], stk[i-1]);
        // cout<<now<<'\n';
        // cout<<now<<' '<<eval(stk[i], now)<<'\n';
        if(now<0) continue;
        if(prv<0 && 0<=now){
            prv=now;
            ans=max(ans, eval(stk[i-1], 0));
        }
        if(l<now){
            ans=max(ans, eval(stk[i-1], l));
            break;
        }
        // cout<<now<<' '<<eval(stk[i], now)<<'\n';
        ans=max(ans, eval(stk[i], now));
        // cout<<'\n';
    }
    // cout<<'\n';
    // for(int i=0; i<(int)stk.size(); i++) cout<<stk[i].first<<' '<<stk[i].second<<'\n';

    // if(stk.size()==1U) ans=max({ans, eval(stk[0], 0), eval(stk[0], l)});
    // if(stk.size()>1U && itst(stk[0], stk[1])<=0) ans=max(ans, eval(stk[0], 0));
    // if(stk.size()>1U && itst(stk.back(), stk[stk.size()-2])>=l) ans=max(ans, eval(stk.back(), l));
    cout<<sqrtl(ans);
    return 0;
}

Subtask #1
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 248 KB Output is correct
2 Correct 3 ms 484 KB Output is correct
3 Correct 3 ms 568 KB Output is correct
4 Incorrect 2 ms 568 KB Output isn't correct

Subtask #2
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 724 KB Output is correct
2 Correct 2 ms 724 KB Output is correct
3 Correct 3 ms 724 KB Output is correct
4 Correct 3 ms 724 KB Output is correct

Subtask #3
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 724 KB Output is correct
2 Incorrect 3 ms 724 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 724 KB Output is correct
2 Incorrect 4 ms 724 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 724 KB Output is correct
2 Incorrect 4 ms 724 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 740 KB Output is correct
2 Incorrect 6 ms 740 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 43 ms 1900 KB Output is correct
2 Incorrect 23 ms 1900 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #8
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 1900 KB Output is correct
2 Correct 23 ms 1900 KB Output is correct
3 Incorrect 31 ms 1904 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #9
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 25 ms 4148 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #10
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 31 ms 4148 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #11
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 34 ms 4148 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #12
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 126 ms 16724 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #13
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 169 ms 16724 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #14
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 220 ms 26532 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #15
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 238 ms 26532 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #16
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 218 ms 28104 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #17
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 239 ms 28104 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #18
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 239 ms 29704 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #19
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 314 ms 29704 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #20
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 326 ms 32840 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #21
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 388 ms 32840 KB Output isn't correct
2 Halted 0 ms 0 KB -