Language: C++

/**
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*/
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cassert>

#define F first
#define S second
#define endl '\n'
#define deb(x) cout<<#x<<' '<<x<<endl;
#define pb push_back

/*
#ifdef IZI_KATKA
#define int __int64_t
#else
#define int __int64
#endif
*/

const long long MOD = 1e9 + 7;
const long long MAXN = 1e6 + 1;
using namespace std;

typedef long long ll;

long long readInt() {
    bool minus1 = false;
    long long result = 0;
    char ch;
    ch = getchar();
    while (true) {
        if (ch == '-') break;
        if (ch >= '0' && ch <= '9') break;
        ch = getchar();
    }
    if (ch == '-') minus1 = true; else result = ch-'0';
    while (true) {
        ch = getchar();
        if (ch < '0' || ch > '9') break;
        result = result*10 + (ch - '0');
    }
    if (minus1)
        return -result;
    else
        return result;
}


int main() {
	#ifdef IZI_KATKA
	assert(freopen("input", "r", stdin));
    assert(freopen("output", "w", stdout));
    #endif
    int n = readInt();
	int nn = 1;
	if (n == 0) {
		cout << 0;
		return 0;
	}
	if (n > 0) {
		while(nn < n) nn *= 2;
		int tmp = log2(nn);
		if (tmp % 2 == 1) nn *= 2;
		string s = "";
		for (int i = 0; i < log2(nn); i++) {
			s += '0';
		}
		nn-=n;
		int L = s.size();
		s[L - 1] = '1';
		if (n % 1) {
			s[0] = '1';	
			nn++;
		} 
		for (int i = s.size()- 1; i >= 0; i --) {
			if (i & 1) {
				if ((1 << i) >= nn)  {
					s[i] = '1';
					nn -= (1 << i);
				}
			}
		}
		cout << s;
	} else {
		while(nn < n) nn *= 2;
		if (log2(nn) % 2 == 0) nn *= 2;
		string s = "";
		for (int i = 0; i < log2(nn); i++) {
			s += '0';
		}
		nn-=n;
		int L = s.size();
		s[L - 1] = '1';
		if (n % 1) {
			s[0] = '1';	
			nn++;
		} 
		for (int i = s.size()- 1; i >= 0; i --) {
			if (i & 1) {
				if ((1 << i) >= nn)  {
					s[i] = '1';
					nn -= (1 << i);
				}
			}
		}
		cout << s;
			
	}
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:106:30: error: invalid operands of types '__gnu_cxx::__enable_if<true, double>::__type' {aka 'double'} and 'int' to binary 'operator%'
  106 |                 if (log2(nn) % 2 == 0) nn *= 2;
      |                     ~~~~~~~~ ^ ~
      |                         |      |
      |                         |      int
      |                         __gnu_cxx::__enable_if<true, double>::__type {aka double}