Submission #962015

#	Time	Username	Problem	Language	Result	Execution time	Memory
962015		roadster	Balloons (CEOI11_bal)	C++17	100 / 100	160 ms	7172 KiB

bal

#include <bits/stdc++.h>
using namespace std;

using vi = vector<int>;
using vvi = vector<vector<int> >;
using pi = pair<int, int>;
using ll = long long;

#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define f first
#define s second
#define pb push_back

const ll MOD = 1e9 + 7;
ll expo(ll x, ll n) {
    ll res = 1LL;
    while (n) {
           if (n % 2){ res = res * x % MOD; }
        x = x * x % MOD;
        n /= 2;
    }
    return res;
}

vector<ll> factorial(int n) {
    vector<ll> fact(n + 1);
    fact[0] = 1;
    for (int i = 1; i <= n; i++) { fact[i] = fact[i - 1] * i % MOD; }
    return fact;
}

vector<ll> mod_inverse(int n, ll fact_n) {
    vector<ll> inv(n + 1);
    inv[n] = expo(fact_n, MOD - 2);
    for (int i = n; i >= 1; i--) {
        inv[i - 1] = inv[i] * i % MOD;
    }
    return inv;
}

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

double calcRadius(pair<double, double> prev, double currPos) {
    return (prev.first - currPos) * (prev.first - currPos) / (4 * prev.second);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    // your code goes here

    int n;
    cin >> n;
    vector<double> res;
    stack<pair<double, double>> st;
    for (int i = 0; i < n; i++) {
        double x, r;
        cin >> x >> r;

        double maxRadius = r;
        while (!st.empty()) {
            auto prev = st.top();
            auto currRadius = calcRadius(prev, x);

            maxRadius = min(maxRadius, currRadius);
            if (maxRadius >= prev.second) {
                st.pop();
                continue;
            } else {
                break;
            }
        }

        st.push({x, maxRadius});
        res.pb(maxRadius);
    }

    cout << fixed << setprecision(3);
    for (double r: res) cout << r << "\n";
    return 0;
}

Compilation message (stderr)

bal.cpp: In function 'void setIO(std::string)':
bal.cpp:43:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bal.cpp:44:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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