Counting Valleys [Hacker Rank]

Question

An avid hiker keeps meticulous records of their hikes. During the last hike that took exactly steps steps, for every step it was noted if it was an uphill,U , or a downhill,D step. Hikes always start and end at sea level, and each step up or down represents a 1 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.

Code

def countingValleys(steps, path):
    # Write your code here
    v = 0 #to check valley
    answer = 0
    for i in range(steps):
        if path[i] == 'U':
            v += 1
            if v == 0: # if v turns - to 0
                answer += 1
        else:
            v -= 1
    return answer           
                

valley를 확인하기 위해 sea level보다 아래에서 sea level과 같아지면 answer에 +1 해준다.