[해커랭크] Jumping on the Clouds

[해커랭크] Jumping on the Clouds

 

https://www.hackerrank.com/challenges/jumping-on-the-clouds/problem?isFullScreen=true

Jumping on the Clouds | HackerRank

 

There is a new mobile game that starts with consecutively numbered clouds. Some of the clouds are thunderheads and others are cumulus. The player can jump on any cumulus cloud having a number that is equal to the number of the current cloud plus  or . The player must avoid the thunderheads. Determine the minimum number of jumps it will take to jump from the starting postion to the last cloud. It is always possible to win the game.

For each game, you will get an array of clouds numbered  if they are safe or  if they must be avoided.

Example

Index the array from . The number on each cloud is its index in the list so the player must avoid the clouds at indices  and . They could follow these two paths:  or . The first path takes  jumps while the second takes . Return .

Function Description

Complete the jumpingOnClouds function in the editor below.

jumpingOnClouds has the following parameter(s):

• int c[n]: an array of binary integers

Returns

• int: the minimum number of jumps required

Input Format

The first line contains an integer , the total number of clouds. The second line contains  space-separated binary integers describing clouds  where .

Constraints

•  
•  
•  

Output Format

Print the minimum number of jumps needed to win the game.

Sample Input 0

7
0 0 1 0 0 1 0

Sample Output 0

4

Explanation 0:
The player must avoid  and . The game can be won with a minimum of  jumps:

Sample Input 1

6
0 0 0 0 1 0

Sample Output 1

3

Explanation 1:
The only thundercloud to avoid is . The game can be won in  jumps:

 

 

 

 

 

그리디 알고리즘으로,

현재 위치에서 점프할 수 있는 만큼 최대한으로 점프하면

최소점프수가 보장되도록 문제 풀이 하였음

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 'jumpingOnClouds' function below.

     *

     * The function is expected to return an INTEGER.

     * The function accepts INTEGER_ARRAY c as parameter.

     */

    public static int jumpingOnClouds(List<Integer> c) {

    // Write your code here

        int jumpCount = 0;

        int i = 0;

        int size = c.size();

        // greedy

        while (i < size - 1) {

            if (i + 2 < size && c.get(i+2) == 0) {  // can jump jump

                i += 2;

            } else {    // can jump

                i += 1;

            }

            jumpCount++;

        }

        return jumpCount;

    }

}

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 n = Integer.parseInt(bufferedReader.readLine().trim());

        List<Integer> c = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))

            .map(Integer::parseInt)

            .collect(toList());

        int result = Result.jumpingOnClouds(c);

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

        bufferedWriter.newLine();

        bufferedReader.close();

        bufferedWriter.close();

    }

}