Add: Perfect Number

Author: openset

problems/perfect-number/perfect_number.go

@@ -1 +1,31 @@
 package problem507
+
+// Solution 1
+func checkPerfectNumber(num int) bool {
+	if num < 6 {
+		return false
+	}
+	sum, mid := 1, num
+	for i := 2; i < mid; i++ {
+		if num%i == 0 {
+			n := num / i
+			sum += i + n
+			if mid > n {
+				mid = n
+			}
+		}
+	}
+	return sum == num
+}
+
+// Solution 2
+func checkPerfectNumber2(num int) bool {
+	m := map[int]bool{
+		6:        true,
+		28:       true,
+		496:      true,
+		8128:     true,
+		33550336: true,
+	}
+	return m[num]
+}

problems/perfect-number/perfect_number_test.go

@@ -1 +1,47 @@
 package problem507
+
+import "testing"
+
+type testType struct {
+	in   int
+	want bool
+}
+
+func TestCheckPerfectNumber(t *testing.T) {
+	tests := [...]testType{
+		{
+			in:   28,
+			want: true,
+		},
+		{
+			in:   6,
+			want: true,
+		},
+		{
+			in:   24,
+			want: false,
+		},
+		{
+			in:   1,
+			want: false,
+		},
+		{
+			in:   33550336,
+			want: true,
+		},
+	}
+	// Solution 1
+	for _, tt := range tests {
+		got := checkPerfectNumber(tt.in)
+		if got != tt.want {
+			t.Fatalf("in: %v, got: %v, want: %v", tt.in, got, tt.want)
+		}
+	}
+	// Solution 2
+	for _, tt := range tests {
+		got := checkPerfectNumber2(tt.in)
+		if got != tt.want {
+			t.Fatalf("in: %v, got: %v, want: %v", tt.in, got, tt.want)
+		}
+	}
+}