Longest-Harmonious-Subsequence

LeetCode

第77天。

今天的题目是Longest Harmonious Subsequence:

We define a harmonious array is an array where the difference between its maximum value and its minimum value is exactly 1.

Now, given an integer array, you need to find the length of its longest harmonious subsequence among all its possible subsequences.

Example 1:
Input: [1,3,2,2,5,2,3,7]
Output: 5
Explanation: The longest harmonious subsequence is [3,2,2,2,3].
Note: The length of the input array will not exceed 20,000.

好像有是一个用hash做的题目：

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int findLHS(vector<int>& nums) {
    unordered_map<int,int> m;
    for(int i = 0;i < nums.size();i++)
        m[nums[i]]++;
    int len = 0;
    for(auto &p:m) {
        if (m.count(p.first + 1) > 0)
            len = max(len,p.second + m[p.first + 1]);
    }
    return len;
}

dicuss中有用sort做的：

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int findLHS(vector<int>& nums) {
    sort(nums.begin(),nums.end());
    int len = 0;
    for(int i = 1, start = 0, new_start = 0; i<nums.size(); i++)
    {

        if (nums[i] - nums[start] > 1)
            start = new_start;
        if (nums[i] != nums[i-1])
            new_start = i;
        if(nums[i] - nums[start] == 1)
            len = max(len, i-start+1);
    }
    return len;
}