LeetCode/go/count-the-number-of-good-subarrays.go

package main

func countGood(nums []int, k int) int64 {
	counters := make(map[int]int)
	count := int64(0)

	same, right := 0, -1
	for _, x := range nums {
		for same < k && right+1 < len(nums) {
			right++
			same += counters[nums[right]]
			counters[nums[right]]++
		}

		if same >= k {
			count += int64(len(nums) - right)
		}

		counters[x]--
		same -= counters[x]
	}

	return count
}