#3191 - Minimum Operations to Make Binary Array Elements Equal to One I

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Array Bit Manipulation Prefix Sum Sliding Window Queue

Problem Description

You are given a binary array nums.

You can do the following operation on the array any number of times (possibly zero):

Choose any 3 consecutive elements from the array and flip all of them.

Flipping an element means changing its value from 0 to 1, and from 1 to 0.

Return the minimum number of operations required to make all elements in nums equal to 1.

If it is impossible, return -1.

Solution

/**
 * @param {number[]} nums
 * @return {number}
 */
var minOperations = function(nums) {
  const result = [...nums];
  let operations = 0;

  for (let i = 0; i < nums.length - 2; i++) {
    if (result[i] === 0) {
      result[i] ^= 1;
      result[i + 1] ^= 1;
      result[i + 2] ^= 1;
      operations++;
    }
  }

  return result.every(num => num === 1) ? operations : -1;
};