add: leetcode 0400 test

leetcode/0400.Nth-Digit/400.Nth Digit_test.go

@@ -0,0 +1,45 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question400 struct {
+	para400
+	ans400
+}
+
+// para 是参数
+type para400 struct {
+	n int
+}
+
+// ans 是答案
+type ans400 struct {
+	ans int
+}
+
+func Test_Problem400(t *testing.T) {
+
+	qs := []question400{
+
+		{
+			para400{3},
+			ans400{3},
+		},
+
+		{
+			para400{11},
+			ans400{0},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 400------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans400, q.para400
+		fmt.Printf("【input】:%v    【output】:%v\n", p.n, findNthDigit(p.n))
+	}
+	fmt.Printf("\n\n\n")
+}