Remove all negative numbers after the first negative number in an array

The

Scala> val a = arraybuffer[int] (1, 2,3, 5, -1, 2, -3, -5) A: scala.collection.mutable.arraybuffer[int]= arraybuffer (1, 2, 3, 5, -1, 2 ,  -3, -5)  scala> :p aste// entering paste mode  (ctrl-d tofinish )  var foundFirstNegative = falseval keepIndexes = for  (i <-  0 untila.length if !foundfirstnegative | |  a (i)  > 0)  #  Description 1yield {if  (A (i)  < 0)   foundfirstnegative =true; i #  Description 2}for  (i <- 0 until  Keepindexes.length) A (i)  = a (keepindexes (i))  #  description 3a.trimend (a.length -  Keepindexes.length) #  Description 4 // exiting paste mode, now interpreting.  Foundfirstnegative: boolean = truekeepindexes:scala.collection.immutable.indexedseQ[int] = vector (0, 1, 2, 3, 4,5) Scala> ares4: Scala.collection.mutable.arraybuffer[int] = arraybuffer (1,&NBSP;2,&NBSP;3,&NBSP;5,&NBSP;-1,&NBSP;2)

Algorithm Description: Avoid the traditional multiple moving array, remove multiple times , the above code design advantage is to find the element that does not meet the criteria index, and then uniformly delete these elements.

illustration 1: The first negative number and all positive numbers will pass through the if guard;

illustration 2: The first negative number passes the If Guard, enters the description 2 code, the foundfirstnegative is set to true, Subsequent negative numbers pass through the If Guard section, and I and if are independent and do not surround the block with blocks;

illustration 3: Set the first KEEPINDEXES.LENGTH element in a to the corresponding integer and the first negative number;

Description 4 : Delete a in keepindexes.length–1 The element that follows the position, and the remainder is the element that is being asked.

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Remove all negative numbers after the first negative number in an array