update

easy/447.number-of-boomerangs.go

@@ -1,3 +1,24 @@
-func numberOfBoomerangs(points [][]int) int {
-    
+func numberOfBoomerangs(points [][]int) (cnt int) {
+	n := len(points)
+	dis := make([][]int, n)
+	for i := 0; i < n; i++ {
+		dis[i] = make([]int, n)
+	}
+	for i := 0; i < n-1; i++ {
+		for j := i + 1; j < n; j++ {
+			dx, dy := points[i][0]-points[j][0], points[i][1]-points[j][1]
+			dis[i][j] = dx*dx + dy*dy
+			dis[j][i] = dis[i][j]
+		}
+	}
+	for i := 0; i < n; i++ {
+		m := make(map[int]int)
+		for j := 0; j < n; j++ {
+			m[dis[i][j]]++
+		}
+		for _, v := range m {
+			cnt += v * (v - 1)
+		}
+	}
+	return
 }

easy/448.find-all-numbers-disappeared-in-an-array.go

@@ -0,0 +1,13 @@
+func findDisappearedNumbers(nums []int) (res []int) {
+	n := len(nums)
+	set := make([]bool, n+1)
+	for _, i := range nums {
+		set[i] = true
+	}
+	for i := 1; i <= n; i++ {
+		if !set[i] {
+			res = append(res, i)
+		}
+	}
+	return
+}