LeetCode——Max Consecutive Ones

LeetCode——Max Consecutive Ones

Question

Given a binary array, find the maximum number of consecutive 1s in this array.

Example 1:

Input: [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.

Note:

The input array will only contain 0 and 1.

The length of input array is a positive integer and will not exceed 10,000

解题思路

用stack求解。

具体实现

class Solution {
public:
    int findMaxConsecutiveOnes(vector<int>& nums) {
        stack<int> st;
        int max_len = 0;
        for (int i : nums) {
            if (i == 0) {
                if (st.size() > max_len)
                    max_len = int(st.size());
                // 清空栈
                while(!st.empty())
                    st.pop();
            } else
                st.push(i);
        }
        return max(int(st.size()), max_len);
    }
};

用一个计数器也可以求解。

class Solution {
public:
    int findMaxConsecutiveOnes(vector<int>& nums) {
        int max=0,cur=0;
        for(int i=0;i<nums.size();i++)
        {
            if(nums[i]&1)
            {
                max=max>++cur?max:cur;
            }
            else cur=0;
        }
        return max;
    }
};

时间复杂度都是O(n)，但是计数器更快一些。