LeetCode75——Day16

一、题目

1004. Max Consecutive Ones III

Given a binary array nums and an integer k, return the maximum number of consecutive 1’s in the array if you can flip at most k 0’s.

Example 1:

Input: nums = [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: nums = [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.

Constraints:

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

二、题解

滑动窗口+前缀和

class Solution {
public:
    int longestOnes(vector<int>& nums, int k) {
        int n = nums.size();
        vector<int> P(n + 1);
        for (int i = 1; i <= n; ++i) {
            P[i] = P[i - 1] + (1 - nums[i - 1]);
        }
        int ans = 0;
        for (int right = 0; right < n; ++right) {
            int left = lower_bound(P.begin(), P.end(), P[right + 1] - k) - P.begin();
            ans = max(ans, right - left + 1);
        }
        return ans;
    }
};
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