Counting Valleys Problem and solution in python

 Counting Valleys Problem: 

Gary is an avid hiker. He tracks his hikes meticulously, paying close attention to small details like topography. During his last hike he took exactly steps. For every step he took, he noted if it was an uphill, , or a downhill, step. Gary's hikes 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 Gary's sequence of up and down steps during his last hike, find and print the number of valleys he walked through. For example, if Gary's path is , he first enters a valley units deep. Then he climbs out an up onto a mountain units high. Finally, he returns to sea level and ends his hike.

Function Description Complete the countingValleys function in the editor below. It must return an integer that denotes the number of valleys Gary traversed.

Solution in Python:

#!/bin/python

import math

import os

import random

import re

import sys

#

# Complete the 'countingValleys' function below.

#

# The function is expected to return an INTEGER.

# The function accepts following parameters:

#  1. INTEGER steps

#  2. STRING path

#

def returnCode(step):

        if step=='U':

            return 1;

        return -1;

def countingValleys(steps, path):

    # Write your code here

     

    level=valley=0

    for element in path:

        code = returnCode(element)

        if level< 0 and level+code == 0:

            valley=valley+1

        level = level+code

    return valley

if __name__ == '__main__':

    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    steps = int(raw_input().strip())

    path = raw_input()

    result = countingValleys(steps, path)

    fptr.write(str(result) + '\n')

    fptr.close()

In C++ the solution is:

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int l;
    string str; 

    cin>>l>>str;
    int height = 0;
    int count = 0;
    for(int i=0;i<l;i++){
        if (str[i]=='U') height++;
        else {
            if (height==0) count++;
            height--;
        }
    }
    if (height<0) 

      count--;

    cout<<count<<endl;

       
    return 0;
}

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.