Puzzle: Sort an array of 0's and 1's in one parse.

Question

Is it possible to arrange the array made up of only 1\'s and 0\'s in descending order within one parse without using auxiliary array?
For example: Suppose you have an ar

Answer 1

#include

using namespace std;

int main() {
    int arr[] = {1, 1, 1, 1, 1, 0, 0, 0};
    int N = sizeof(arr) / sizeof(arr[0]);
    int p = 0, q = 1;

while (q != N) {
    if (arr[p] > arr[q]) {
        arr[p] = 0;
        arr[q] = 1;
        p++;
        q++;
    }
    else {
        q++;
        if (arr[p] == 0)
            p++;
    }
}

for (int i = 0; i < N; i++)
    cout << arr[i];

return 0;