vue3 最长递增子序列 diff优化

//vue3优化版（回头我会完善下算法思路）

function getSequence(arr) {
    const p = arr.slice()
    const result = [0]
    let i, j, u, v, c
    const len = arr.length
    for (i = 0; i < len; i++) {
        const arrI = arr[i]
        if (arrI !== 0) {
            j = result[result.length - 1]
            if (arr[j] < arrI) {
                p[i] = j
                result.push(i)
                continue
            }
            u = 0
            v = result.length - 1
            while (u < v) {
                c = ((u + v) / 2) | 0
                if (arr[result[c]] < arrI) {
                    u = c + 1
                } else {
                    v = c
                }
            }
            if (arrI < arr[result[u]]) {
                if (u > 0) {
                    p[i] = result[u - 1]
                }
                result[u] = i
            }
        }
    }
    u = result.length
    v = result[u - 1]
    while (u-- > 0) {
        result[u] = v
        v = p[v]
    }
    return result
}

console.log(getSequence([10, 9, 2, 5, 3, 7, 101, 18]));

//算法原型——基础算法版

//Objective is to find the longest increasing subsequence in an array.

let nums = [10,9,2,5,3,7,101,18]


//O(n^2) solution that uses dynamic programming to figure out if we want the 
//element in the subsequence or not.

if (nums.length == 0) {
    return 0
}

//Every element initially starts with a subsequence of length 1
let dp = new Array(nums.length).fill(1)

//Use a nested iterator to compare all pairs of elements in the array
for (let i = 0; i < nums.length; i++) {
    for (let j = 0; j < i; j++) {
        //If nums[i] = 5 && nums[j] = 2, then we can choose to add
        //the previous subsequence to the current one
        if (nums[i] > nums[j]) {
            dp[i] = Math.max(dp[i], dp[j] + 1)    
        }
    }
}

return Math.max(...dp)