longest increasing subsequence

longest-increasing-subsequence.js

function longestIncreasingSubsequence(arr) {
  return arr.slice(0, arr.lastIndexOf(-1)).reduce(
    (acc, val) => {
      if (acc.prev == null) {
        return { ...acc, prev: val }
      }

      if (val > acc.prev) {
        return { ...acc, count: acc.count + 1, prev: val }
      } else {
        if (acc.count > acc.largestSequence) {
          return { count: 1, prev: val, largestSequence: acc.count }
        }

        return { ...acc, prev: val, count: 1 }
      }
    },
    {
      count: 1,
      largestSequence: 1
    }
  )
}

const input = [22, 35, 4, 16, 42, 3, -1]
console.log(input)
const x = longestIncreasingSubsequence(input)
console.log(x)