title: golang with compile error: undefined: strings in strings.trim
body: <p>I try to use <strong>golang</strong> deal with this problem <a href="https://leetcode.com/problems/reverse-words-in-a-string-iii/#/description" rel="noreferrer">557. Reverse Words in a String III </a> 
  my code as below:</p>
  
  <pre><code>import "fmt"
  import  ss "strings"
  
  func reverseWords(s string) string {
      words := ss.Split(s," ");
      res := "";
      for i:=0; i &lt; len(words);i++{
          curWord := ss.Split(words[i],"");
          for j:=len(curWord)-1; j &gt;= 0;j--{
              res += curWord[j];
          }
          if(i!=len(words)-1){
              res += " ";
          }
      }
      return res;
  }
  
  func main(){
      s := "Let's take LeetCode contest";
      fmt.Println(reverseWords(s));
  }
  </code></pre>
  
  <p>Everything is ok in my pc, it can pass compile at least. <br>
  <strong>However</strong>, when I submit in leetcode it tell me :</p>
  
  <pre><code> Line 67: undefined: strings in strings.Trim 
  </code></pre>
  
  <p>I google this error but get nothing relevant info. As a beginner in golang, I need help. Everything will be appreciated.</p>