update solution.md

data/2.算法中阶/4.leetcode-栈与队列/1.227-基本计算器 II/solution.md

@@ -12,6 +12,7 @@
 
 <pre>
 <strong>输入：</strong>s = "3+2*2"
+
 <strong>输出：</strong>7
 </pre>
 
@@ -19,6 +20,7 @@
 
 <pre>
 <strong>输入：</strong>s = " 3/2 "
+
 <strong>输出：</strong>1
 </pre>
 
@@ -26,6 +28,7 @@
 
 <pre>
 <strong>输入：</strong>s = " 3+5 / 2 "
+
 <strong>输出：</strong>5
 </pre>