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An avid hiker keeps meticulous records of their hikes. During the last hike that took exactly steps, for every step it was noted if it was an uphill, , or a downhill, step. Hikes always start and end at sea level, and each step up or down represents a unit change in altitude. We define the following terms:

  • A mountain is a sequence of consecutive steps above sea level, starting with a step up from sea level and ending with a step down to sea level.
  • A valley is a sequence of consecutive steps below sea level, starting with a step down from sea level and ending with a step up to sea level.

Given the sequence of up and down steps during a hike, find and print the number of valleys walked through.

Example


The hiker first enters a valley units deep. Then they climb out and up onto a mountain units high. Finally, the hiker returns to sea level and ends the hike.

Function Description

Complete the countingValleys function in the editor below.

countingValleys has the following parameter(s):

  • int steps: the number of steps on the hike
  • string path: a string describing the path

Returns

  • int: the number of valleys traversed

Input Format

The first line contains an integer , the number of steps in the hike.
The second line contains a single string , of characters that describe the path.

Constraints

Sample Input

8
UDDDUDUU

Sample Output

1

Explanation

If we represent _ as sea level, a step up as /, and a step down as \, the hike can be drawn as:

_/\      _
   \    /
    \/\/

The hiker enters and leaves one valley.

Limbajul de programare folosit: python3

Cod:

import sys

data = sys.stdin.read().strip().split()
n = int(data[0])
path = data[1]
level = 0
valleys = 0
for ch in path:
    if ch == 'U':
        level += 1
        if level == 0:
            valleys += 1
    else:
        level -= 1
print(valleys)

Scor obtinut: 1.0

Submission ID: 464552803

Link challenge: https://www.hackerrank.com/challenges/counting-valleys/problem

Counting Valleys