-
Notifications
You must be signed in to change notification settings - Fork 0
/
longest-increasing-subsequence.js
52 lines (43 loc) · 1.11 KB
/
longest-increasing-subsequence.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
// Given an unsorted array of integers, find the length of longest increasing subsequence.
//
// Example:
//
//
// Input: [10,9,2,5,3,7,101,18]
// Output: 4
// Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4.
//
// Note:
//
//
// There may be more than one LIS combination, it is only necessary for you to return the length.
// Your algorithm should run in O(n2) complexity.
//
//
// Follow up: Could you improve it to O(n log n) time complexity?
//
var lengthOfLIS = function(nums) {
const dp = []
for (const num of nums) {
if (!dp.length || num > dp[dp.length - 1]) {
dp.push(num)
continue
}
const index = binarySearch(dp, num)
dp[index] = num
}
return dp.length
};
const binarySearch = (arr, target) => {
let low = 0
let high = arr.length - 1
while (low < high) {
const mid = Math.floor((high - low) / 2) + low
if (arr[mid] >= target) {
high = mid
} else {
low = mid + 1
}
}
return low
}