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Create 1512-number-of-good-pairs.kt

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	`1`	`+// rolling count`
	`2`	`+classSolution {`
	`3`	`+funnumIdenticalPairs(nums:IntArray):Int {`
	`4`	`+val count=HashMap<Int,Int>()`
	`5`	`+var total=0`
	`6`	`+`
	`7`	`+for (nin nums) {`
	`8`	`+ count[n]?.let {`
	`9`	`+ total+= it`
	`10`	`+ }`
	`11`	`+ count[n]= count.getOrDefault(n,0)+1`
	`12`	`+ }`
	`13`	`+`
	`14`	`+return total`
	`15`	`+ }`
	`16`	`+}`
	`17`	`+`
	`18`	`+// count and use arithmetic sequence`
	`19`	`+classSolution {`
	`20`	`+funnumIdenticalPairs(nums:IntArray):Int {`
	`21`	`+val count=HashMap<Int,Int>().apply {`
	`22`	`+for (nin nums) {`
	`23`	`+this[n]= getOrDefault(n,0)+1`
	`24`	`+ }`
	`25`	`+ }`
	`26`	`+`
	`27`	`+var res=0`
	`28`	`+for (cin count.values) {`
	`29`	`+ res+= c* (c-1)/2`
	`30`	`+ }`
	`31`	`+`
	`32`	`+return res`
	`33`	`+ }`
	`34`	`+}`
	`35`	`+`
	`36`	`+// brute force`
	`37`	`+classSolution {`
	`38`	`+funnumIdenticalPairs(nums:IntArray):Int {`
	`39`	`+var count=0`
	`40`	`+`
	`41`	`+for (iin0 until nums.size) {`
	`42`	`+for (jin i+1 until nums.size) {`
	`43`	`+if (nums[i]== nums[j]) {`
	`44`	`+ count++`
	`45`	`+ }`
	`46`	`+ }`
	`47`	`+ }`
	`48`	`+`
	`49`	`+return count`
	`50`	`+ }`
	`51`	`+}`

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