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常见排序算法

2019-01-13  本文已影响0人  Grit0821

1.冒泡排序

两两摸头法

a <- {
  '0':6,
  '1':3,
  '2':7,
  '3':11,
  '4':4,
  '5':9,
  'length':6
}
轮数n <- 1
while (n < a['length'])
  选中的数字的下标i <- 0
  while (i < a['length'] - n)
    if (a[i] < a[i+1])
      i <- i+1
    else
      t <- a[i]
      a[i] <- a[i+1]
      a[i+1] <- t
      i <- i+1
    end
    n <- n+1
  end
end

2.选择排序法

一指禅法

a <- {
  '0':3,
  '1':5,
  '2':1,
  '3':7,
  '4':2,
  '5':6,
  'length':6
}
轮数n <- 1
while (n < a['length'])
  minIndex <- n-1
  index <- minIndex+1
  while (index < a['length'])
    if(a[minIndex] < a[index])
      index <- index+1
    else
      minIndex <- index
      index <- index+1
    end
  t <- a[n-1]
  a[n-1] <- a[minIndex]
  a[minIndex] <- t
  index <- index+1
  end
print a
end

3.计数排序法

Hash当桶

a <- {
  '0':0,
  '1':5,
  '2':1,
  '3':7,
  '4':2,
  '5':5,
  'length':6
}
hash <- {

}
//入桶
index <- 0
while (index < a['length'])
  number <- a['index']
  if hash[number] == undefined
    hash[number] <- 1
  else
    hash[number] <- hash[number] + 1
  end
  index <- index + 1
end
//出桶
index2 <- 0
//确定hash长度(最大的数+1)
max <-findMax(a)
/*
findMax(a):
  index3 <- 0
  max <- a['index3']
  while(index3 < a['length']-1)
    if(a['index3'] < a['index3'+1])
      max <- a['index3'+1]
    else
      max <- a['index3']
  index3 <- index3+1
  end
*/
while(index2 < max+1)
  count <- hash[index2]
  if count != undefined
    countIndex <- 0
    while(countIndex < count)
      newArr.push(index2)
      countIndex <- countIndex+1
    end
  end
  index2 <- index2+1
print newArr
end

4.桶排序

a <- {
  '0':0,
  '1':5,
  '2':1,
  '3':7,
  '4':2,
  '5':5,
  'length':6
}
hash <- {

}
//入桶
capacity <- 10 //每个桶存放的数字范围
findMaxMin(a): //找出数组a中最大值和最小值
  index3 <- 0
  max <- a['index3']
  min <- a['index3']
  while(index3 < a['length']-1)
    if(a['index3'] > max)
      max <- a['index3']
    if(a['index3'] < min)
      min <- a[index3]
  index3 <- index3+1
  end

bucketCount <- 取整[(max-min)/capacity] //确定桶的数量

index <- 0
while(index < a['length'])
  bucketIndex <- 0
  while(bucketIndex < bucketCount)
    if a[index] <= (min+capacity*(bucketIndex+1)) && a[index] > (min+capacity*bucketIndex)
      if(bucket[bucketIndex] == undefined)
        bucket[bucketIndex] <- []
      else
        bucket[bucketIndex].push(a[index])
      end
    end
  bucketIndex <- bucketIndex+1
  end
index <- index+1
end

//用冒泡排序将桶内数据排序
轮数n <- 1
while (n < bucketIndex)
  minIndex <- n-1
  index <- minIndex+1
  while (index < bucketIndex)
    if(bucket[bucketIndex][minIndex] < bucket[bucketIndex][index])
      index <- index+1
    else
      minIndex <- index
      index <- index+1
    end
  t <- bucket[bucketIndex][n-1]
  bucket[bucketIndex][n-1] <- bucket[bucketIndex][minIndex]
  bucket[bucketIndex][minIndex] <- t
  index <- index+1
  end
end

//出桶
outBucket <- 0
while(outBucket < bucketCount)
  if bucket[outBucket] != undefined
    outBucketIndex <- 0
    while(outBucketIndex < bucket[outBucket].length)
      newArr.push(bucket[outBucket][outBucketIndex])
    end
  outBucket <- outBucket+1
  end
print newArr
end

5.堆排序

堆排序就是把最大堆堆顶的最大数取出,将剩余的堆继续调整为最大堆,再次将堆顶的最大数取出,这个过程持续到剩余数只有一个时结束。在堆中定义以下几种操作:

  1. 最大堆调整(Max-Heapify):将堆的末端子节点作调整,使得子节点永远小于父节点
  2. 创建最大堆(Build-Max-Heap):将堆所有数据重新排序,使其成为最大堆
  3. 堆排序(Heap-Sort):移除位在第一个数据的根节点,并做最大堆调整的递归运算
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