Commit 46450ba

committed

[ACCEPTED][Problem 1995] Count Special Quadruplets

1 parent 2654770 commit 46450baCopy full SHA for 46450ba

File tree

+24

-0

lines changed

+24

-0

lines changed

Lines changed: 24 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,8 @@`
`1`	`1`	`package easy`
`2`	`2`
`3`	`3`	`object CountSpecialQuadruplets1995 {`
	`4`	`+ //1.brute force`
	`5`	`+ //Time: O(N^4); Space: O(1)`
`4`	`6`	`fun countQuadruplets(nums: IntArray): Int {`
`5`	`7`	`val n = nums.size`
`6`	`8`	`var count = 0`
`@@ -19,4 +21,26 @@ object CountSpecialQuadruplets1995 {`
`19`	`21`
`20`	`22`	`return count`
`21`	`23`	`}`
	`24`	`+`
	`25`	`+ fun countQuadrupletsSOL2(nums: IntArray): Int {`
	`26`	`+ val freqMap = HashMap<Int,Int>()`
	`27`	`+ val n = nums.size`
	`28`	`+ var count = 0`
	`29`	`+`
	`30`	`+ for(i in n-2 downTo 1)`
	`31`	`+ {`
	`32`	`+ for (j in i+1 until n)`
	`33`	`+ {`
	`34`	`+ val sum = nums[j]-nums[i]`
	`35`	`+ freqMap[sum]=freqMap.getOrDefault(sum,0)+1`
	`36`	`+ }`
	`37`	`+`
	`38`	`+ for (j in i-2 downTo 0)`
	`39`	`+ {`
	`40`	`+ val sum = nums[j]+nums[i-1]`
	`41`	`+ count+=freqMap.getOrDefault(sum,0)`
	`42`	`+ }`
	`43`	`+ }`
	`44`	`+ return count`
	`45`	`+ }`
`22`	`46`	`}`

Comments

(0)