Submission #916291

#	Time	Username	Problem	Language	Result	Execution time	Memory
916291		asdasdqwer	Mobile (BOI12_mobile)	C++14	8 / 100	1079 ms	48336 KiB

mobile

#include <bits/stdc++.h>
using namespace std;
    
#define int int64_t
#define pii array<int,2>
    
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n,t;cin>>n>>t;
    vector<pii> v(n);
    for (auto &x:v)cin>>x[0]>>x[1];
    
    double l = 1;
    double r = 1e15;
    vector<bool> rem(n, false);
    
    while (abs(l-r) > 0.00001) {
        double m = (l+r)/2.0;
        int i=0;
        vector<array<double,2>> start;
        for (auto &x:v) {
            if ((double)abs(x[1]) >= m) {
                rem[i]=true;
            }
    
            else {
                double aa=abs(x[1]);
                double dis=sqrt(m*m-aa*aa);
                array<double,2> pos1 = {x[0]-dis,x[0]+dis};
                if ((pos1[0] < 0.0 && pos1[1] < 0.0) || (pos1[0] > (double)t && pos1[1] > (double)t)) {
                    rem[i]=true;
                }
    
                else {
                    pos1[0]=max(pos1[0], 0.0);
                    pos1[1]=min(pos1[1], (double)t);
                    start.push_back(pos1);
                }
            }
    
            i++;
        }
    
        start.push_back({0.0, 0.0});
        start.push_back({(double)t,(double)t});
    
        sort(start.begin(),start.end());
        // cout<<m<<" "<<l<<" "<<r<<"\n";
        // for (auto &x:start) {
        //     cout<<x[0]<<" "<<x[1]<<"\n";
        // }
        // cout<<"\n";
        // for (auto &x:v) {
        //     cout<<x[0]<<" "<<x[1]<<"\n";
        // }
        // cout<<"\n\n";

    
        array<double,2> pos={0.0, 0.0};
        bool possible=true;
    
        for (auto &x:start) {
            if (x[0] <= pos[1]) {
                pos[1]=max(pos[1], x[1]);
            }
    
            else {
                possible=false;
                break;
            }
        }
    
        if (possible) {
            r=m;
            // int cnt=0;
            // int pt=0;
            // for (int i=0;i<n;i++) {
            //     if (rem[i]) {
            //         cnt++;
            //     }
                
            //     else if (cnt != 0) {
            //         swap(v[i], v[pt]);
            //     }
    
            //     if (!rem[i]) {
            //         pt++;
            //     }
            // }
    
            // n -= cnt;
    
            // while (v.size() != n){
            //     v.pop_back();
            //     rem.pop_back();
            // }
    
            // for (int i=0;i<n;i++) {
            //     rem[i]=false;
            // }
        }
    
        else {
            l=m;
            for (int i=0;i<n;i++) {
                rem[i]=false;
            }
        }
    }

    r = round(r * 10000.0) / 10000.0;
    cout<<r<<"\n";
}

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 0 / 4
• Subtask 4: 0 / 4
• Subtask 5: 0 / 4
• Subtask 6: 0 / 5
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• Subtask 21: 0 / 5