# leetcode\_1004

Given an array A of 0s and 1s, we may change up to K values from 0 to 1.

Return the length of the longest (contiguous) subarray that contains only 1s.

Example 1:

Input: A = \[1,1,1,0,0,0,1,1,1,1,0], K = 2 Output: 6 Explanation: \[1,1,1,0,0,1,1,1,1,1,1] Bolded numbers were flipped from 0 to 1. The longest subarray is underlined. Example 2:

Input: A = \[0,0,1,1,0,0,1,1,1,0,1,1,0,0,0,1,1,1,1], K = 3 Output: 10 Explanation: \[0,0,1,1,1,1,1,1,1,1,1,1,0,0,0,1,1,1,1] Bolded numbers were flipped from 0 to 1. The longest subarray is underlined.

Note:

1 <= A.length <= 20000 0 <= K <= A.length A\[i] is 0 or 1

## Solutions

1. **sliding window**
2. The problem equals to find the length of the longest window with at most `k` zeros.

```cpp
class Solution {
public:
    int longestOnes(vector<int>& A, int K) {
        int i = 0, j = 0, res = 0, cnt = 0;
        while (j < A.size()) {
            if (A[j++] == 0 && ++cnt > K) {
                while (A[i++] != 0);
                cnt--;
            }
            res = max(res, j - i);
        }

        return res;
    }
};
```