Car

#include <bits/stdc++.h>

using namespace std;

static inline double func(double x)
{
    return exp(x) + sqrt(x);
}

int main() {
    cin.sync_with_stdio(false);

    // e^x + sqrt(x) < 3^x + x
    // let y be the upper limit of our search
    // 3^x + x = y
    // 3^x + x^1

    // first find the upper bound by doubling the initial guess until
    // we have something workable
    // then locate the change point with binary search

    double lim = 1.0; // litres
    double d;
    cin >> d;

    while (func(lim) < d) {
        lim *= 2.0;
    }

    // cout << lim << "\n";

    double b = lim;
    double x = 0.0;

    while (abs(b) > 1e-8) {
        b /= 2.0;

        if (func(x + b) < d) {
            // cout << "less\n";
            x += b;
        }

        // cout << x << "\n";
        // cout << "b: " << b << "\n";
    }

    printf("%.12f\n", x);
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED