Commit 1e0e4bb

committed

2972. Count the Number of Incremovable Subarrays II

1 parent 8ec751a commit 1e0e4bbCopy full SHA for 1e0e4bb

File tree

+67

-0

lines changed

+67

-0

lines changed

Lines changed: 67 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,67 @@`
	`1`	`+class Solution {`
	`2`	`+`
	`3`	`+ // Solution by Sergey Leschev`
	`4`	`+ // 2972. Count the Number of Incremovable Subarrays II`
	`5`	`+`
	`6`	`+ // Two pointer`
	`7`	`+ // O(N)`
	`8`	`+`
	`9`	`+ func countSortedArrays(_ arr1: [Int], _ arr2: [Int]) -> Int {`
	`10`	`+ let n1 = arr1.count`
	`11`	`+ let n2 = arr2.count`
	`12`	`+`
	`13`	`+ var result = 0`
	`14`	`+ var i = 0`
	`15`	`+ var j = 0`
	`16`	`+`
	`17`	`+ while i < n1 && j < n2 {`
	`18`	`+ if arr1[i] < arr2[j] {`
	`19`	`+ result += (n2 - j)`
	`20`	`+ i += 1`
	`21`	`+ } else {`
	`22`	`+ j += 1`
	`23`	`+ }`
	`24`	`+ }`
	`25`	`+`
	`26`	`+ return result`
	`27`	`+ }`
	`28`	`+`
	`29`	`+ func incremovableSubarrayCount(_ nums: [Int]) -> Int {`
	`30`	`+ let n = nums.count`
	`31`	`+`
	`32`	`+ if n == 1 {`
	`33`	`+ return 1`
	`34`	`+ }`
	`35`	`+`
	`36`	`+ var i = 0`
	`37`	`+ var j = n - 1`
	`38`	`+ var arr1: [Int] = []`
	`39`	`+ var arr2: [Int] = []`
	`40`	`+`
	`41`	`+ while (i + 1) < n && nums[i] < nums[i + 1] {`
	`42`	`+ arr1.append(nums[i])`
	`43`	`+ i += 1`
	`44`	`+ }`
	`45`	`+ arr1.append(nums[i])`
	`46`	`+`
	`47`	`+ while (j - 1) >= 0 && nums[j] > nums[j - 1] {`
	`48`	`+ arr2.append(nums[j])`
	`49`	`+ j -= 1`
	`50`	`+ }`
	`51`	`+ arr2.append(nums[j])`
	`52`	`+ arr2.reverse()`
	`53`	`+`
	`54`	`+ if j < i {`
	`55`	`+ let ans = n * (n + 1) / 2`
	`56`	`+ return ans`
	`57`	`+ }`
	`58`	`+`
	`59`	`+ var ans = 0`
	`60`	`+ ans += arr1.count // 1`
	`61`	`+ ans += arr2.count // 2`
	`62`	`+ ans += countSortedArrays(arr1, arr2) // 3`
	`63`	`+ ans += 1 // 4`
	`64`	`+`
	`65`	`+ return ans`
	`66`	`+ }`
	`67`	`+}`

Comments

(0)