[HackerEarth] Easy - A good array(JavaScript)

Problem

You are given an array A which consists of N elements. Each element of array is either zero or one. Your task is to convert the given array into a good array with a minimum cost.

Good array: In a good array, select any subarray of even length M and the sum of elements in the subarray will be M/2.

In order to transform an array to good array, you can perform the following two operations as many times as you want:

1.  Choose any index 1≤i≤N and if it is currently 0, then convert it to 1 for X coins.
2.  Choose any index 1≤i≤N and if it is currently 1, then convert it to 0 for Y coins.

Your task is to minimize the cost of transformation of an array to good array.

 

Input format

• The first line contains T denoting the number of test cases.
• The first line of each test case contains three space-separated integers N, X, and Y.
• The second line of each test case consists of N space-separated integers of array A.

 

Output format

For each test case, print one line denoting the minimum cost to transform array  into a good array.

 

Constraints

1≤T≤100

1≤N≤$10^4$

0≤$A_{i}$≤1

1≤X,Y≤$10^9$

 

Sample Input/Output

Input	Output
2 2 1 1 1 1 2 1 1 0 1	1 0

 

Time Limit: 1

Memory Limit: 256

Source Limit:

 

Explanation

First test case: Array is [1,1], there is only one subarray which is of even length (2), i.e. complete subarray [1,1], it is not good array because for a subarray of size M i.e 2 in our case, sum must be M/2 i.e 1. But sum is 2 for this subarray, so this does not follow property of good subarray.
So here we need convert array to either [1,0] or [0,1], cost is 1 in either case.

Second test case: Array is [0,1], there is only one subarray which is of even length (2), i.e. complete subarray [0,1], it is  good array because for a subarray of size M i.e 2 in our case, sum must be M/2 i.e 1. Here sum is 2 for this subarray, so this does  follow property of good subarray.
So we don't need to perform any operation.

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My Code

process.stdin.resume();
process.stdin.setEncoding("utf-8");
var stdin_input = "";

process.stdin.on("data", function (input) {
  stdin_input += input; // Reading input from STDIN
});

process.stdin.on("end", function () {
  main(stdin_input);
});

function main(input) {
  let data = input.split("\n");
  let input_cnt = 0;
  let t = data[input_cnt++];
  while (t--) {
    let [n, x, y] = data[input_cnt++].split(" ").map((item) => parseInt(item));
    let a = data[input_cnt++].split(" ");
    let ans1 = 0;
    for (let i = 0; i < a.length; i++) {
      if (i % 2 === 1 && a[i] === "0") ans1 += x;
      if (i % 2 === 0 && a[i] === "1") ans1 += y;
    }
    let ans2 = 0;
    for (let i = 0; i < a.length; i++) {
      if (i % 2 === 1 && a[i] === "1") ans2 += y;
      if (i % 2 === 0 && a[i] === "0") ans2 += x;
    }
    console.log(Math.min(ans1, ans2));
  }
}