package leetcode

func numberOfBoomerangs(points [][]int) int {
	res := 0
	for i := 0; i < len(points); i++ {
		record := make(map[int]int, len(points))
		for j := 0; j < len(points); j++ {
			if j != i {
				record[dis(points[i], points[j])]++
			}
		}
		for _, r := range record {
			res += r * (r - 1)
		}
	}
	return res
}

func dis(pa, pb []int) int {
	return (pa[0]-pb[0])*(pa[0]-pb[0]) + (pa[1]-pb[1])*(pa[1]-pb[1])
}