text: //
  //  Find_the_Difference.c
  //  MyLeetCode
  //
  //  Created by poco on 2019/2/11.
  //  Copyright © 2019 zyy. All rights reserved.
  //
  
  char findTheDifference(char* s, char* t) {
      
      int result,i;
      int s_len = strlen(s);
      int t_len = strlen(t);
      
      //X ^ X = 0
      //X ^ 0 = X
      //相同的抵消变0，单独的和0异或，还是单独的
      
      for(i = 0;i < s_len;i++)
      {
          result ^= s[i];
      }
      
      for(i = 0;i < t_len;i++)
      {
          result ^= t[i];
      }
      
      return (char)result;
      
  }
  