Max Consecutive Ones LeetCode

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



Input 1: nums = [1,1,0,1,1,1]

Output 1: 3

Explanation 1: The first two digits or the last three digits are consecutive 1s. The maximum number of consecutive 1s is 3.


Input 2: nums = [1,0,1,1,0,1]

Output 2: 2


class Solution {
    public int findMaxConsecutiveOnes(int[] nums) {
        int maxCount = 0;
        int currentCount = 0;

        for (int num : nums) {
            if (num == 1) {
                currentCount++;           // Keep counting 1s
                maxCount = Math.max(maxCount, currentCount); // Update max
            } else {
                currentCount = 0;         // Reset count on 0
            }
        }

        return maxCount;
    }
}

💡 Time Complexity:

  • O(n) → where n is the length of the array

💡 Space Complexity:

  • O(1) → no extra space used

🔍 Key Idea:

  • Keep a currentCount of consecutive 1s

  • When you hit 0, reset currentCount to 0

  • Always update maxCount if currentCount is higher

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