# include iostream usingnamespace std; voidquick_sort(int l, int r, int q[]){ if (l >= r) return; int i = r - 1, j = r + 1, key = q[l + r >> 1]; while( i <= j){ do i ++; while (q[i] < key ); do j --; while (q[j] > key); if (q[i] >= q[j]) swap(q[i], q[j]) } if (i < j) swap(q[i], key); quick_sort(l, j); quick_sort(j + 1, r); }