[LeetCode] Max Consecutive Ones 最大连续1的个数

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

这道题让我们求最大连续1的个数,不是一道难题。我们可以遍历一遍数组,用一个计数器cnt来统计1的个数,方法是如果当前数字为0,那么cnt重置为0,如果不是0,cnt自增1,然后每次更新结果res即可,参见代码如下:

解法一:

class Solution {
public:
int findMaxConsecutiveOnes(vector<int>& nums) {
int res = , cnt = ;
for (int num : nums) {
cnt = (num == ) ? : cnt + ;
res = max(res, cnt);
}
return res;
}
};

由于是个二进制数组,所以数组中的数字只能是0或1,那么连续1的和跟个数相等,所以我们可以计算和,通过加上num,再乘以num来计算,如果当前数字是0,那么sum就被重置为0,还是要更新结果res,参见代码如下:

解法二:

class Solution {
public:
int findMaxConsecutiveOnes(vector<int>& nums) {
int res = , sum = ;
for (int num : nums) {
sum = (sum + num) * num;
res = max(res, sum);
}
return res;
}
};

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