添加 18 题

leetcode/0507.Perfect-Number/507. Perfect Number.go

@@ -0,0 +1,24 @@
+package leetcode
+
+import "math"
+
+// 方法一
+func checkPerfectNumber(num int) bool {
+	if num <= 1 {
+		return false
+	}
+	sum, bound := 1, int(math.Sqrt(float64(num)))+1
+	for i := 2; i < bound; i++ {
+		if num%i != 0 {
+			continue
+		}
+		corrDiv := num / i
+		sum += corrDiv + i
+	}
+	return sum == num
+}
+
+// 方法二 打表
+func checkPerfectNumber_(num int) bool {
+	return num == 6 || num == 28 || num == 496 || num == 8128 || num == 33550336
+}