Problem:
Score : 300 points

Problem Statement

In a flower bed, there are N flowers, numbered 1,2,......,N. Initially, the heights of all flowers are 0.
You are given a sequence h=\{h_1,h_2,h_3,......\} as input. You would like to change the height of Flower k to h_k for all k (1 \leq k \leq N), by repeating the following "watering" operation:

Specify integers l and r. Increase the height of Flower x by 1 for all x such that l \leq x \leq r.

Find the minimum number of watering operations required to satisfy the condition.

Constraints

1 \leq N \leq 100

0 \leq h_i \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
h_1 h_2 h_3 ...... h_N

Output

Print the minimum number of watering operations required to satisfy the condition.

Sample Input 1

4
1 2 2 1

Sample Output 1

2

The minimum number of watering operations required is 2.
One way to achieve it is:

Perform the operation with (l,r)=(1,3).

Perform the operation with (l,r)=(2,4).

Sample Input 2

5
3 1 2 3 1

Sample Output 2

5

Sample Input 3

8
4 23 75 0 23 96 50 100

Sample Output 3

221

Solution in Scala (2.11.7) (judge verdict: Wrong Answer)

object Main extends App {
  var n = scala.io.StdIn.readInt()
  var s = scala.io.StdIn.readLine()
  val inputArray =  s.split(" ").map(_.toInt)
  var i = 0
  var seqVar = Seq.empty[Int]
  for (i<-0 to n - 1) {
    seqVar :+= 0
  }

  def addWater(s: Seq[Int]): Seq[Int] = {
    var tempArrayIndex = Seq.empty[Int]
    var maxArrayIndex = Seq.empty[Int]
    for(i<-0 to n - 1) {
      if (s(i) == inputArray(i)) {
        if (tempArrayIndex.size > maxArrayIndex.size) {
          maxArrayIndex = tempArrayIndex
        }
        tempArrayIndex = Seq.empty[Int]
      } else if (i == (n - 1)) {
        tempArrayIndex :+= i
        if (tempArrayIndex.size > maxArrayIndex.size) {
          maxArrayIndex = tempArrayIndex
        }
      } else {
        tempArrayIndex :+= i
      }
    }
    s.zipWithIndex.map{ h =>
      if (maxArrayIndex.find(_ == h._2).isDefined) {
        h._1 + 1
      }else {
        h._1
      }
    }
  }
  def compareSeq(s1: Seq[Int], s2: Seq[Int]): Boolean= {
    for(i<-0 to n - 1) {
      if(s1(i) != s2(i)) {
        return false
      }
    }
    true
  }

  def judgeSeq(s: Seq[Int]): Unit = {
    i += 1
    val seqAfterWater = addWater(s)
    if (compareSeq(inputArray, seqAfterWater)) {
      println(i)
    } else {
      judgeSeq(seqAfterWater)
    }
  }
  judgeSeq(seqVar)
}