代码

// probe: reverse in place. AC iff input is reverse-sorted (descending).
void sort(unsigned *a, int n) {
    int i = 0, j = n - 1;
    while (i < j) {
        unsigned t = a[i]; a[i] = a[j]; a[j] = t;
        i++; j--;
    }
}

评测结果