485. Max Consecutive Ones

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.

Solutions

Solution 1

Python Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10

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

Java Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14

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

C++ Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15

class Solution {
public:
    int findMaxConsecutiveOnes(vector<int>& nums) {
        int cnt = 0, ans = 0;
        for (int v : nums) {
            if (v == 1) {
                ++cnt;
            } else {
                ans = max(ans, cnt);
                cnt = 0;
            }
        }
        return max(ans, cnt);
    }
};

Go Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12

func findMaxConsecutiveOnes(nums []int) int {
	ans, cnt := 0, 0
	for _, v := range nums {
		if v == 1 {
			cnt++
		} else {
			ans = max(ans, cnt)
			cnt = 0
		}
	}
	return max(ans, cnt)
}

TypeScript Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13

function findMaxConsecutiveOnes(nums: number[]): number {
    let res = 0;
    let count = 0;
    for (const num of nums) {
        if (num === 0) {
            res = Math.max(res, count);
            count = 0;
        } else {
            count++;
        }
    }
    return Math.max(res, count);
}

Rust Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15

impl Solution {
    pub fn find_max_consecutive_ones(nums: Vec<i32>) -> i32 {
        let mut res = 0;
        let mut count = 0;
        for num in nums {
            if num == 0 {
                res = res.max(count);
                count = 0;
            } else {
                count += 1;
            }
        }
        res.max(count)
    }
}

JavaScript Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17

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

PHP Code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18

class Solution {
    /**
     * @param Integer[] $nums
     * @return Integer
     */
    function findMaxConsecutiveOnes($nums) {
        $tmp = $max = 0;
        for ($i = 0; $i < count($nums); $i++) {
            if ($nums[$i] == 1) {
                $tmp++;
            } else {
                $max = max($tmp, $max);
                $tmp = 0;
            }
        }
        return max($tmp, $max);
    }
}