int j, left = 0, right = len - 1; while (left < right) { for (j = left; j < right; j++) if (arr[j] > arr[j + 1]) swap(arr[j], arr[j + 1]); right--; for
{sgn}(n)\left[{\frac {a}{\left|n\right|}}\right]} 这里的 s g n {\displaystyle \mathrm {sgn} } 是符号函数,因此 r = a − | n | [ a | n | ] {\displaystyle r=a-|n|\left[{\frac