m% = 16000 DIM SHARED s(m%) RANDOMIZE TIMER FOR i% = 1 TO m%     s(i%) = RND NEXT QSort3 1, m% 调用排序 --------------------------------------------------- 第一种: 标准的递归形式 SUB QuickSort (l%, h%) IF l% < h% THEN   IF h% - l% = 1 THEN      IF s(l%) > s(h%) THEN SWAP s(l%), s(h%)   ELSE      r% = INT(RND * (h% - l% + 1)) + l%      SWAP s(h%), s(r%)      p = s(h%)      i% = l%      j% = h%      DO       DO WHILE (i% < j%) AND (s(i%) <= p)          i% = i% + 1       LOOP       DO WHILE (j% > i%) AND (s(j%) >= p)          j% = j% - 1       LOOP       IF i% < j% THEN SWAP s(i%), s(j%)      LOOP WHILE i% < j%      SWAP s(i%), s(h%)      IF (i% - l%) < (h% - i%) THEN         QuickSort l%, i% - 1         QuickSort i% + 1, h%      ELSE         QuickSort i% + 1, h%         QuickSort l%, i% - 1      END IF   END IF END IF END SUB ------------------------------------------------------- 第二种: 用数组替换递归 SUB QSort2 (l%, m%) DIM q%((LOG(m%) / LOG(2)) * 10) h% = m% DO IF l% < h% THEN   IF h% - l% = 1 THEN      IF s(l%) > s(h%) THEN SWAP s(l%), s(h%)      l% = h% + 1      h% = q%(k%)      k% = k% - 1   ELSE      r% = (h% + l%) \ 2      SWAP s(h%), s(r%)      p = s(h%)      i% = l%      j% = h%      DO       DO WHILE (i% < j%) AND (s(i%) <= p)          i% = i% + 1       LOOP       DO WHILE (j% > i%) AND (s(j%) >= p)          j% = j% - 1       LOOP       IF i% < j% THEN SWAP s(i%), s(j%)      LOOP WHILE i% < j%      SWAP s(i%), s(h%)      IF i% - l% > 1 THEN         k% = k% + 1         q%(k%) = h%         h% = i% - 1      ELSE         l% = i% + 1      END IF   END IF ELSE      l% = h% + 1      h% = q%(k%)      k% = k% - 1 END IF LOOP UNTIL l% >= (m% - 1) END SUB ----------------------------------------------------- 第三种: 保留动态特性的替换 SUB QSort3 (l%, m%) h% = m% DIM q%((LOG(h%) / LOG(2)) * 10, 1) DO IF l% < h% THEN   IF h% - l% = 1 THEN      IF s(l%) > s(h%) THEN SWAP s(l%), s(h%)      GOTO 10   ELSE      p = s(h%)      i% = l%      j% = h% - 1      DO       DO WHILE (i% < j%) AND (s(i%) <= p)          i% = i% + 1       LOOP       DO WHILE (j% > i%) AND (s(j%) >= p)          j% = j% - 1       LOOP       IF i% < j% THEN SWAP s(i%), s(j%)      LOOP WHILE i% < j%      SWAP s(i%), s(h%)      IF i% - l% < h% - l% THEN         k% = k% + 1         q%(k%, 0) = i% + 1         q%(k%, 1) = h%         h% = i% - 1      ELSE         k% = k% + 1         q%(k%, 0) = l%         q%(k%, 1) = i% - 1         l% = i% + 1      END IF   END IF ELSE 10      l% = q%(k%, 0)      h% = q%(k%, 1)      k% = k% - 1 END IF LOOP UNTIL k% < 0 END SUB -------------------------------------------------------- 在 Qsort2 形式中,因为按顺序分组,所以失去了动态的特性 而标志数组的在一般的情况下是不会溢出的,除非是恶意的定位 这个时候最大层数有可能达到 m/2 层 而普通情况下应该最多只有 2*(log(m)/log(2)) 层 为了保留动态的处理顺序,变形出 Qsort3 用了二维数组去保存上下两界,能不能减少层数,也不好说 因为加了一维来代替层数去了, 而因为处理数据的不定原因,我还去掉了 rnd 的动态 在 Qsort3 里,我还加了一句 goto 只是为了省几下键盘,在这里使用还算情有可愿吧. 更改形式的目的是为了避免堆栈溢出的麻烦, 但在 XP 下好像连标准递归都没出现溢出现象, 不知道是什么回事. 而 Qsort2, Qsort3 不用递归的好处就是连数组都可以作为参数 省略共享,如果在递归中不使用共享而用参数形式的话还得处理一些地址问题 欢迎大家提出意见,因为我文化水平实现不高,希望能得到大家的指点.

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