Submission #1307054

#	Time	Username	Problem	Language	Result	Execution time	Memory
1307054		shk1384	Balloons (CEOI11_bal)	C++20	10 / 100	151 ms	4412 KiB

bal

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb(x) push_back(x)
#define mp(x, y) make_pair(x, y)
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#define dbg(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << endl;
const int N=1e6+10;
//const ll mod=998244353;
const ll mod=1000000007;
const int intinf=2e9;
const ll llinf=9e18;
const ld eps=2e-7;

const ld is_query = -(1LL<<62);
struct line {
    ld m, b;
    mutable function<const line*()> succ;
    bool operator<(const line& rhs) const {
        if (rhs.b != is_query) return m < rhs.m;
        const line* s = succ();
        if (!s) return 0;
        ld x = rhs.m;
        return b - s->b < (s->m - m) * x;
    }
};

struct dynamic_hull : public multiset<line> { // will maintain upper hull for maximum
    const ld inf = LLONG_MAX;
    bool bad(iterator y) {
        auto z = next(y);
        if (y == begin()) {
            if (z == end()) return 0;
            return y->m == z->m && y->b <= z->b;
        }
        auto x = prev(y);
        if (z == end()) return y->m == x->m && y->b <= x->b;

		/* compare two lines by slope, make sure denominator is not 0 */
        ld v1 = (x->b - y->b);
        if (y->m == x->m) v1 = x->b > y->b ? inf : -inf;
        else v1 /= (y->m - x->m);
        ld v2 = (y->b - z->b);
        if (z->m == y->m) v2 = y->b > z->b ? inf : -inf;
        else v2 /= (z->m - y->m);
        return v1 >= v2;
    }
    void insert_line(ld m, ld b) {
        auto y = insert({ m, b });
        y->succ = [=] { return next(y) == end() ? 0 : &*next(y); };
        if (bad(y)) { erase(y); return; }
        while (next(y) != end() && bad(next(y))) erase(next(y));
        while (y != begin() && bad(prev(y))) erase(prev(y));
    }
    ld eval(ld x) {
        auto l = *lower_bound((line) { x, is_query });
        return l.m * x + l.b;
    }
};

dynamic_hull hull;

void solve(){
    int n;
    cin >> n;
    cout << fixed << setprecision(3);
    for(int i = 0; i < n; i++){
        ld x, r;
        cin >> x >> r;
        if(i == 0){
            cout << r << "\n";
            hull.insert_line((ld)-1 / (2 * sqrtl(r)), x / (2 * sqrtl(r)));
        }else{
            ld ans = hull.eval(x);
            cout << min(ans * ans, r) << "\n";
            hull.insert_line((ld)-1 / (2 * sqrtl(r)), x / (2 * sqrtl(r)));
        }
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    solve();
    return 0;
}

Compilation message (stderr)

bal.cpp: In lambda function:
bal.cpp:76:19: warning: implicit capture of 'this' via '[=]' is deprecated in C++20 [-Wdeprecated]
   76 |         y->succ = [=] { return next(y) == end() ? 0 : &*next(y); };
      |                   ^
bal.cpp:76:19: note: add explicit 'this' or '*this' capture

• Subtask 1: 0 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10