Submission #1116614

#	Time	Username	Problem	Language	Result	Execution time	Memory
1116614		pemguimn	Balloons (CEOI11_bal)	C++14	0 / 100	3 ms	504 KiB

bal

#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 5;

int n, x[N], r[N];

long double ans[N];

long double calc(int i, int j){
    long double lo = 0, hi = r[j];
    long double dx = abs(x[j] - x[i]);
    for(int t = 0; t < 100; t++){
        long double mid = (lo + hi) / 2;
        long double dy = abs(mid - ans[i]);
        if(dx * dx + dy * dy >= (mid + ans[i]) * (mid + ans[i])){
            lo = mid;
        } else{
            hi = mid;
        }
    }
    return lo;
}

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    #ifndef Pemgu
        #define task "bal"
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    #endif // Pemgu

    cin >> n;
    for(int i = 1; i <= n; i++){
        cin >> x[i] >> r[i];
        ans[i] = r[i];
    }

    stack<int> st;
    for(int i = 1; i < n; i++){
        long double reach = r[i];
        if(st.size()) reach = min(reach, calc(st.top(), i));
        ans[i] = reach;

        while(st.size() && calc(st.top(), i + 1) > calc(i, i + 1)) st.pop();
        st.push(i);
    }
    while(st.size()){
        ans[n] = min(ans[n], calc(st.top(), n));
        st.pop();
    }

    for(int i = 1; i <= n; i++)
        cout << setprecision(3) << fixed << ans[i] << "\n";

    return 0;
}

Compilation message (stderr)

bal.cpp: In function 'int main()':
bal.cpp:32:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bal.cpp:33:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 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