In this post, We are going to solve HackerRank Counting Valleys Problem.
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, 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.
Example
steps = 8 path = [DDUUUUUDDD]
The hiker first enters a valley 2 units deep. Then they climb out and up onto a mountain 2 units high. Finally, the hiker returns to sea level and ends the hike.
Function Description
Complete the counting alleys function in the editor below.
counting Valleys 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 integer steps, the number of steps in the hike.
The second line contains a single string path, of steps characters that describe the path.
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.
Counting Valleys C Solution
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
int main() {
/* Enter your code here. Read input from STDIN. Print output to STDOUT */
int n;
scanf("%d\n",&n);
char *height = malloc(sizeof(char) * n);
for(int height_i = 0; height_i < n; height_i++){
scanf("%c",&height[height_i]);
}
int level = 0;
int count = 0;
int valley = 0;
for(int height_i = 0; height_i < n; height_i++){
if (height[height_i] == 'D')
{
if( level == 0 && valley == 0)
{
valley = 1;
}
level--;
}
else if (height[height_i] == 'U')
{
if (level == -1 && valley == 1)
{
count++;
valley = 0;
}
level++;
}
}
printf("%d",count);
return 0;
}Counting Valleys C++ Solution
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
int steps;
cin >> steps;
int level = 0;
int valleys = 0;
char c;
for (int i = 0; i < steps; i++) {
cin >> c;
if (c == 'U') {
level++;
if (level == 0) {
valleys++;
}
} else if (c == 'D') {
level--;
}
}
cout << valleys << '\n';
return 0;
}Counting Valleys C Sharp Solution
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Counting_Valleys
{
class Program
{
static void Main(string[] args)
{
int sea_level=1, cnt_valley=0,level=1,i=0;
int n = int.Parse(Console.ReadLine());
string walk = Console.ReadLine();
while(i<n)
{
if(sea_level<level)
{
if (walk[i] == 'U')
level++;
else
level--;
}
else if(sea_level>level)
{
if (walk[i] == 'U')
level++;
else
level--;
if (sea_level == level)
cnt_valley++;
}
else
{
if (walk[i] == 'U')
level++;
else
level--;
}
i++;
}
Console.WriteLine(cnt_valley);
}
}
}
Counting Valleys Java Solution
import java.io.*;
import java.util.*;
public class Solution {
public static void main(String[] args) {
Scanner s=new Scanner(System.in);
int steps=s.nextInt();
char[] seq= s.nextLine().toCharArray();
seq= s.nextLine().toCharArray();
int level=0;
int valleys=0;
boolean valleyStart=false;
//System.out.println("jaja");
for(int i=0;i<steps;i++)
{
//System.out.println(level+" "+seq[i]);
if(level==0 && seq[i]=='D'){
valleyStart=true;
}
if(level==-1 && seq[i]=='U' && valleyStart){
valleyStart=false;
valleys++;
}
if(seq[i]=='D'){
level--;
}
else{
level++;
}
}
System.out.println(valleys);
}
}Counting Valleys JavaScript Solution
function processData(input) {
//Enter your code here
var steps = input.split("\n")[1];
steps = steps.split("");
var valleys = 0;
var level = 0;
steps.map(function(step){
if(level == 0 && step == "D"){
valleys += 1;
}
if(step == "D"){
level -= 1;
}
if(step == "U"){
level += 1;
}
});
console.log(valleys);
}
process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
_input += input;
});
process.stdin.on("end", function () {
processData(_input);
});Counting Valleys Python Solution
first =input()
second=input()
count_1 =0
count_2 =0
below_sea = False
for element in range(0,len(second)):
if second[element] == "U":
count_1 += 1
if second[element] == "D":
count_1 -=1
if count_1 < 0:
if not below_sea :
count_2 +=1
below_sea = True
else:
below_sea =False
print(count_2)Other Solutions
