comefrom: <awangdev>28. Implement strStr()_1.java
code: public int strStr(String haystack, String needle) {
          if (needle == null || needle.length() == 0) {
              return 0;
          }
          if (needle.length() > haystack.length()) {
              return -1;
          }
          int n = haystack.length();
          int m = needle.length();
          for (int i = 0; i < n; i++) { 
              if (n - i < m) {
                  return -1;
              }
              if (haystack.charAt(i) != needle.charAt(0)) {
                  continue;
              }
              
              if (haystack.substring(i, i + m).equals(needle)) { 
                  return i;
              }
          }
          return -1;
      }
masked: public int sample_funcname ( String var_1 , String var_2 ) {
    if ( var_2 == null || var_2 . length ( ) == 0 ) {
      return 0 ;
    }
    if ( var_2 . length ( ) > var_1 . length ( ) ) {
      return - 1 ;
    }
    int var_7 = var_1 . length ( ) ;
    int var_8 = var_2 . length ( ) ;
    for ( int var_9 = 0 ;
    var_9 < var_7 ;
    var_9 ++ ) {
      if ( var_7 - var_9 < var_8 ) {
        return - 1 ;
      }
      if ( var_1 . charAt ( var_9 ) != var_2 . charAt ( 0 ) ) {
        continue ;
      }
      if ( var_1 . substring ( var_9 , var_9 + var_8 ) . equals ( var_2 ) ) {
        return var_9 ;
      }
    }
    return - 1 ;
  }
  