485. Max Consecutive Ones

Problem Description

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

Example 1:

Input: nums = [1,1,0,1,1,1]
Output: 3
Explanation: The first two digits or the last three digits are consecutive 1s. The maximum number of consecutive 1s is 3.

Example 2:

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

Constraints:

• 1 <= nums.length <= 10⁵
• nums[i] is either 0 or 1.

Python Solution

class Solution:
    def findMaxConsecutiveOnes(self, nums: List[int]) -> int:
        max_count = 0
        current_count = 0
        
        for num in nums:
            if num == 1:
                current_count += 1
                max_count = max(max_count, current_count)
            else:
                current_count = 0
        
        return max_count

Java Solution

class Solution {
    public int findMaxConsecutiveOnes(int[] nums) {
        int maxCount = 0;
        int currentCount = 0;
        
        for (int num : nums) {
            if (num == 1) {
                currentCount++;
                maxCount = Math.max(maxCount, currentCount);
            } else {
                currentCount = 0;
            }
        }
        
        return maxCount;
    }
}

C++ Solution

class Solution {
public:
    int findMaxConsecutiveOnes(vector& nums) {
        int maxCount = 0;
        int currentCount = 0;
        
        for (int num : nums) {
            if (num == 1) {
                currentCount++;
                maxCount = max(maxCount, currentCount);
            } else {
                currentCount = 0;
            }
        }
        
        return maxCount;
    }
};

JavaScript Solution

/**
 * @param {number[]} nums
 * @return {number}
 */
var findMaxConsecutiveOnes = function(nums) {
    let maxCount = 0;
    let currentCount = 0;
    
    for (const num of nums) {
        if (num === 1) {
            currentCount++;
            maxCount = Math.max(maxCount, currentCount);
        } else {
            currentCount = 0;
        }
    }
    
    return maxCount;
};

C# Solution

public class Solution {
    public int FindMaxConsecutiveOnes(int[] nums) {
        int maxCount = 0;
        int currentCount = 0;
        
        foreach (int num in nums) {
            if (num == 1) {
                currentCount++;
                maxCount = Math.Max(maxCount, currentCount);
            } else {
                currentCount = 0;
            }
        }
        
        return maxCount;
    }
}