[bus710] Week 14

counting-bits/bus710.go

@@ -0,0 +1,53 @@
+package hello
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func countBits(n int) []int {
+	r := make([]int, 0)
+
+	for i := range n + 1 {
+		b := fmt.Sprintf("%b", i)
+		cnt := strings.Count(string(b), "1")
+		r = append(r, cnt)
+	}
+
+	return r
+}
+
+func Test_countBits(t *testing.T) {
+	type args struct {
+		n int
+	}
+	tests := []struct {
+		name string
+		args args
+		want []int
+	}{
+		{
+			name: "case 1",
+			args: args{
+				n: 2,
+			},
+			want: []int{0, 1, 1},
+		},
+		{
+			name: "case 2",
+			args: args{
+				n: 5,
+			},
+			want: []int{0, 1, 1, 2, 1, 2},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := countBits(tt.args.n); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("countBits() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}