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HackerRank Candies interview preparation kit problem solution

In this HackerRank Candies Interview preparation kit problem you need to complete the candies function.


HackerRank Candies interview preparation kit solution


Problem solution in Python programming.

N = int(input())
a = []
while N>0:
	a.append(int(input()))
	N -= 1
N = len(a)
left, right, num = [[0 for i in range(N)] for j in range(3)]
p = 1
while p<N:
	if a[p] > a[p-1]:
		left[p] = left[p-1] + 1
	p += 1
p = N-2
while p>=0:
	if a[p] > a[p+1]:
		right[p] = right[p+1] + 1
	p -= 1
p = 0
while p<N:
	num[p] = 1 + max(left[p], right[p])
	p += 1

print(sum(num))



Problem solution in Java Programming.

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 candies function below.
    static long candies(int n, int[] arr) {

  int[] candies = new int[n];
  candies[0] = 1;
  for (int i = 1; i < n; i++) {
    if (arr[i] > arr[i - 1]) {
      candies[i] = candies[i - 1] + 1;
    } else {
      candies[i] = 1;
    }
  }

  for (int i = n - 2; i >= 0; i--) {
    if (arr[i] > arr[i + 1] && candies[i] <= candies[i + 1]) {
      candies[i] = candies[i + 1] + 1;
    }
  }

  long sum = 0;
  for (int c : candies) {
    sum += c;
  }
  return sum;
}

    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")));

        int n = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        int[] arr = new int[n];

        for (int i = 0; i < n; i++) {
            int arrItem = scanner.nextInt();
            scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
            arr[i] = arrItem;
        }

        long result = candies(n, arr);

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

        bufferedWriter.close();

        scanner.close();
    }
}


Problem solution in C++ programming.

#include <iostream>
#include <vector>
using namespace std;
int nums[100001]; // ratings
int allocated[100001]; // candies given. defaults to 0 (not processed)
vector<int> pos_by_rating[100001];
int main()
{
	int N;
	cin >> N;
	
	for (int x = 0; x < N; x++)
	{
		cin >> nums[x];
		allocated[x] = 0;
		pos_by_rating[nums[x]].push_back(x);
	}

	for (int rating = 1; rating <= 100000; rating++)
	{
		for (int q = 0; q < pos_by_rating[rating].size(); q++)
		{
			int pos = pos_by_rating[rating][q];
			int m = 0;
			if (pos > 0 && nums[pos-1] < nums[pos])
			{
				m = max(m, allocated[pos-1]);
			}

			if (pos < N-1 && nums[pos+1] < nums[pos])
			{
				m = max(m, allocated[pos+1]);
			}

			allocated[pos] = m+1;
		}
	}
		
	int sum = 0;
	for (int x = 0; x < N; x++)
	{
		//cout << allocated[x] << endl;
		sum += allocated[x];
	}
	cout << sum << endl;

	return 0;
}


Problem solution in C programming.

#include <stdio.h>
#include <stdlib.h>

#define MAXN 100000

struct stu{
    int id;
    int rating;
};

int comp( const void*p1, const void*p2){
    return ((struct stu*)p1)->rating - ((struct stu*)p2)->rating;
}

struct stu student[MAXN];
int candies[MAXN];
int ratings[MAXN];

int main(int argc, char *argv[])
{
    int N;
    int i,j;
    int candy;
    int id;
    long long sumcandies = 0;

    scanf("%d",&N);
    for(i = 0; i < N; i++){
        scanf("%d",&student[i].rating);
        student[i].id = i;
        ratings[i] = student[i].rating;
    }

    qsort(student,N,sizeof(struct stu),comp);
    
    for(i = 0; i < N; i++){
        id = student[i].id;
        candy = 1;

        if(id > 0){
            if(candies[id-1] != 0 && ratings[id] > ratings[id-1]){
                candy = candies[id-1] + 1;
            }
        }

        if(id < N-1){
            if(candies[id+1] != 0 && ratings[id] > ratings[id+1] &&
               candy <= candies[id+1]){
                candy = candies[id+1] + 1;
            }
        }

        sumcandies += candy;
        candies[id] = candy;
    }

    printf("%lld\n",sumcandies);
    return 0;
}


Problem solution in JavaScript programming.

function processData(input) {
    //Enter your code here
    var arr = input.split('\n');
    var sum = 1, tempRank = 1, peakPos = 1, peakVal = 1;
    for (var i = 2; i < arr.length; i++) {
        if (parseInt(arr[i]) > parseInt(arr[i-1])) {
            tempRank++;
            sum += tempRank;
            peakPos = i;
            peakVal = tempRank;
 //          console.log("bigger: " + sum);
        } else if (parseInt(arr[i]) < parseInt(arr[i-1])) {
            if (tempRank > 1) {
                peakVal--;
                sum++;
            } else {
                sum += (i - peakPos);
                peakVal--;
                if (peakVal == 0) {
                    peakVal = 1;
                    sum++;
                }
            }
            tempRank = 1;
//           console.log("smaller: " + sum);
        } else {
           /* if (tempRank > 1) {
                peakVal--;
                if (peakVal == 0) {
                    peakVal = 1;
                    sum++;
                }
            }*/
            
            peakVal = 1;
            peakPos = i;
            tempRank = 1;
            sum++;
 //             console.log("equal: " + sum);
        }
    }
    
    console.log(sum);
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});


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