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300.最长上升子序列.go
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300.最长上升子序列.go
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/*
* @lc app=leetcode.cn id=300 lang=golang
*
* [300] 最长上升子序列
*
* https://leetcode-cn.com/problems/longest-increasing-subsequence/description/
*
* algorithms
* Medium (41.26%)
* Likes: 180
* Dislikes: 0
* Total Accepted: 12.8K
* Total Submissions: 31K
* Testcase Example: '[10,9,2,5,3,7,101,18]'
*
* 给定一个无序的整数数组,找到其中最长上升子序列的长度。
*
* 示例:
*
* 输入: [10,9,2,5,3,7,101,18]
* 输出: 4
* 解释: 最长的上升子序列是 [2,3,7,101],它的长度是 4。
*
* 说明:
*
*
* 可能会有多种最长上升子序列的组合,你只需要输出对应的长度即可。
* 你算法的时间复杂度应该为 O(n^2) 。
*
*
* 进阶: 你能将算法的时间复杂度降低到 O(n log n) 吗?
*
*/
func lengthOfLIS(nums []int) int {
n := len(nums)
if n <= 0 {
return 0
}
lowest := make([]int, n)
lowest[0] = nums[0]
length := 1
for i := 1; i < n; i++ {
if nums[i] > lowest[length-1] {
lowest[length] = nums[i]
length++
} else {
j := binarySearch(lowest, nums[i], length) + 1
lowest[j] = nums[i]
}
}
return length
}
func binarySearch(nums []int, target int, n int) int {
lo, hi := 0, n
for lo < hi {
mi := (lo + hi) >> 1
if nums[mi] < target {
lo = mi + 1
} else {
hi = mi
}
}
return hi - 1
}