Cerinta completa

Goodland is a country with a number of evenly spaced cities along a line. The distance between adjacent cities is unit. There is an energy infrastructure project planning meeting, and the government needs to know the fewest number of power plants needed to provide electricity to the entire list of cities. Determine that number. If it cannot be done, return -1.

You are given a list of city data. Cities that may contain a power plant have been labeled . Others not suitable for building a plant are labeled . Given a distribution range of , find the lowest number of plants that must be built such that all cities are served. The distribution range limits supply to cities where distance is less than k.

Example

Each city is unit distance from its neighbors, and we’ll use based indexing. We see there are cities suitable for power plants, cities and . If we build a power plant at , it can serve through because those endpoints are at a distance of and . To serve , we would need to be able to build a plant in city or . Since none of those is suitable, we must return -1. It cannot be done using the current distribution constraint.

Function Description

Complete the pylons function in the editor below.

pylons has the following parameter(s):

  • int k: the distribution range
  • int arr[n]: each city’s suitability as a building site

Returns

  • int: the minimum number of plants required or -1

Input Format

The first line contains two space-separated integers and , the number of cities in Goodland and the plants’ range constant.
The second line contains space-separated binary integers where each integer indicates suitability for building a plant.

Constraints

  • Each .

Subtask

  • for of the maximum score.

Output Format

Print a single integer denoting the minimum number of plants that must be built so that all of Goodland’s cities have electricity. If this is not possible for the given value of , print .

Sample Input

STDIN         Function
-----         --------
6 2           arr[] size n = 6, k = 2
0 1 1 1 1 0   arr = [0, 1, 1, 1, 1, 0]

Sample Output

2

Explanation

Cities , , , and are suitable for power plants. Each plant will have a range of . If we build in cities cities, and , then all cities will have electricity.

Limbajul de programare folosit: java8

Cod:

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Solution {

  // Complete the pylons function below.
  static int pylons(int k, int[] arr) {
    int counter = 0;
    int index = 0;
    int notCovered = 1;
    int lastAvailable = -1;
    while (index < arr.length) {
      if (arr[index] == 1) {
        lastAvailable = index;
      }

      if (notCovered >= k) {
        if (lastAvailable == -1) {
          return -1;
        }
        notCovered = - (k - 1) + (index - lastAvailable) + 1;
        index++;
        counter++;
        lastAvailable = -1;
      } else if (index == arr.length - 1) {
        if (notCovered > 0) {
          if (lastAvailable != 0) {
            counter++;
          } else {
            return -1;
          }
        }
        index++;
      } else {
        notCovered++;
        index++;
      }
    }
    return counter;
  }

  private static final Scanner scanner = new Scanner(System.in);

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

    String[] nk = scanner.nextLine().split(" ");

    int n = Integer.parseInt(nk[0]);

    int k = Integer.parseInt(nk[1]);

    int[] arr = new int[n];

    String[] arrItems = scanner.nextLine().split(" ");
    scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

    for (int i = 0; i < n; i++) {
      int arrItem = Integer.parseInt(arrItems[i]);
      arr[i] = arrItem;
    }

    int result = pylons(k, arr);

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

    bufferedWriter.close();

    scanner.close();
  }
}

Scor obtinut: 1.0

Submission ID: 464604517

Link challenge: https://www.hackerrank.com/challenges/pylons/problem

Goodland Electricity