Max Consecutive Ones¶

Problem Link

Description¶

Given a binary array nums, return the maximum number of consecutive 1's in the array.

Approach 1: Single Pass with Counter¶

• Time Complexity: O(n)
• Space Complexity: O(1)

This approach iterates through the array a single time, using a counter to track the current streak of consecutive ones.

• If the current element is a 1, we increment the counter.
• If the current element is a 0, it breaks the streak. We then compare the counter to our maxValue to see if we've found a new maximum, and then reset the counter to 0.

After the loop finishes, we do one final check of counter against maxValue to account for cases where the array ends with a streak of ones.

function findMaxConsecutiveOnes(nums: number[]): number {
  let counter = 0;
  let maxValue = 0;
  for (let i = 0; i < nums.length; i++) {
    let value = nums[i];
    if (value !== 0) {
      counter++;
    } else {
      maxValue = Math.max(counter, maxValue);
      counter = 0;
    }
  }
  // Final check in case the array ends with a streak of 1s
  return Math.max(counter, maxValue);
}

// Example 1
console.log(findMaxConsecutiveOnes([1, 1, 0, 1, 1, 1])); // 3

// Example 2
console.log(findMaxConsecutiveOnes([1, 0, 1, 1, 0, 1])); // 2