[HackerRank] Counting Valleys _Java8

 

 

Problem

 

 

 

 

Need two integers: one for keeping track of the number of valleys, and another for tracking current position.

 

Let the hiker start at position 0. 

"U" represents +1, "D" represents -1.

 

Since we only care about the number of valleys completed and not mountains, we want to know when the hiker climbs out of a valley... which would be the moment position -1 becomes 0.

 

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'countingValleys' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts following parameters:
     *  1. INTEGER steps
     *  2. STRING path
     */

    public static int countingValleys(int steps, String path) {
    int valley = 0;
    int currPos = 0;
    String ar[] = path.split("");
    for(String s:ar) {
        if(s.equals("U")) {
            currPos++;
            if(currPos == 0)
            valley++;
        }
        else 
            currPos--;

    }
    
    return valley;

    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int steps = Integer.parseInt(bufferedReader.readLine().trim());

        String path = bufferedReader.readLine();

        int result = Result.countingValleys(steps, path);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}