Leetcode  290. Word Pattern 

Given a pattern and a string str, find if str follows the same pattern.

Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.

Examples:

1. pattern = "abba", str = "dog cat cat dog" should return true.
2. pattern = "abba", str = "dog cat cat fish" should return false.
3. pattern = "aaaa", str = "dog cat cat dog" should return false.
4. pattern = "abba", str = "dog dog dog dog" should return false.

<pre name="code" class="java"> public boolean wordPattern(String pattern, String str) {   boolean flag = false;   int length1 = pattern.length();   String[] str1 = str.split(" ");   int length2 = str1.length;   int count = 0;   HashMap map1 = new HashMap();   HashMap map2 = new HashMap();   int[] array1= new int[length1];   int[] array2= new int[length2];   if(length1 != length2)   flag = false;   else{      for(int i = 0; i < length1; i++){   if(map1.containsKey(String.valueOf(pattern.charAt(i)))){  array1[i] = map1.get(String.valueOf(pattern.charAt(i)));   }   else{   map1.put(String.valueOf(pattern.charAt(i)), i);   array1[i] = i;   }      if(map2.containsKey(str1[i])){   array2[i] = map2.get(str1[i]);   }   else{   map2.put(str1[i], i);   array2[i] = i;   }   }       for(int i = 0; i < length1; i++){   if(array1[i] == array2[i]){   count ++;   }   }   if(count == length1){   flag = true;   }   }     return flag;   }