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57 lines
1.6 KiB
Markdown
Executable File
57 lines
1.6 KiB
Markdown
Executable File
# [594. Longest Harmonious Subsequence](https://leetcode.com/problems/longest-harmonious-subsequence/)
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## 题目
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We define a harmounious array as an array where the difference between its maximum value and its minimum value is **exactly** 1.
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Now, given an integer array, you need to find the length of its longest harmonious subsequence among all its possible [subsequences](https://en.wikipedia.org/wiki/Subsequence).
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**Example 1**:
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Input: [1,3,2,2,5,2,3,7]
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Output: 5
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Explanation: The longest harmonious subsequence is [3,2,2,2,3].
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**Note**: The length of the input array will not exceed 20,000.
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## 题目大意
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和谐数组是指一个数组里元素的最大值和最小值之间的差别正好是1。现在，给定一个整数数组，你需要在所有可能的子序列中找到最长的和谐子序列的长度。说明: 输入的数组长度最大不超过20,000.
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## 解题思路
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- 在给出的数组里面找到这样一个子数组：要求子数组中的最大值和最小值相差 1 。这一题是简单题。先统计每个数字出现的频次，然后在 map 找相差 1 的 2 个数组的频次和，动态的维护两个数的频次和就是最后要求的子数组的最大长度。
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## 代码
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```go
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package leetcode
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func findLHS(nums []int) int {
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if len(nums) < 2 {
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return 0
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}
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res := make(map[int]int, len(nums))
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for _, num := range nums {
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if _, exist := res[num]; exist {
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res[num]++
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continue
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}
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res[num] = 1
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}
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longest := 0
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for k, c := range res {
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if n, exist := res[k+1]; exist {
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if c+n > longest {
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longest = c + n
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}
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}
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}
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return longest
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}
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``` |