counting valleys | asboyer.com

\(O(n)\) solution in Python to the counting valleys problem from HackerRank:


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 def countingValleys(steps, path):
    level = 0
    valleys = 0
    for i in range(steps):     
        if path[i] == 'U':
            level += 1
        else:
            level -= 1
        if path[i] == 'U' and level == 0:
            valleys += 1

    return valleys

if __name__ == '__main__':
    steps = 8
    path = 'UDDDUDUU'
    print(countingValleys(steps, path)) # 1