Easy) 1512. Number of Good Pairs

leetcode.com/problems/number-of-good-pairs/

Number of Good Pairs - LeetCode

javascript

/**
 * @param {number[]} nums
 * @return {number} 
 */
const numIdenticalPairs = (nums) => {
  const pairs = {}
  for (let i = 0; i < nums.length; i++) {
    pairs[nums[i]] ? pairs[nums[i]] += 1 : pairs[nums[i]] = 1
  }
  let numGoodPairs = 0
  const pairNums = Object.values(pairs)
  for (let i = 0; i < pairNums.length; i++) {
    numGoodPairs += (pairNums[i] * (pairNums[i] - 1)) / 2
  }
  return numGoodPairs
}

typescript

interface Pairs {
  [key: string]: number
}

const numIdenticalPairsTS = (nums: number[]): number => {
  const pairs: Pairs = {}
  for (let i = 0; i < nums.length; i++) {
    pairs[nums[i]] ? pairs[nums[i]] += 1 : pairs[nums[i]] = 1
  }
  let numGoodPairs: number = 0
  const pairNums = Object.keys(pairs)
  for (let i = 0; i < pairNums.length; i++) {
    numGoodPairs += (pairs[pairNums[i]] * (pairs[pairNums[i]] - 1)) / 2
  }
  return numGoodPairs
}

golang

func numIdenticalPairs(nums []int) int {
	goodPairs := 0
	pairs := make([]int, 101)
	for _, num := range nums {
		pairs[num]++
	}
	for _, pairsNum := range pairs {
		if pairsNum > 1 {
			goodPairs += pairsNum * (pairsNum - 1) / 2
		}
	}
	return goodPairs
}