Given two strings, write a method to decide if one is a permutation of the other.
Example
Example 1:
Input: "abcd", "bcad"
Output: True
Example 2:
Input: "aac", "abc"
Output: False
思路:count比较一下就可以;
public class Solution {
/**
* @param A: a string
* @param B: a string
* @return: a boolean
*/
public boolean Permutation(String A, String B) {
if(A == null && B == null) return true;
if(A == null || B == null) return false;
if(A.length() != B.length()) return false;
HashMap<Character, Integer> mapa = new HashMap<Character, Integer>();
for(int i = 0; i < A.length(); i++){
char c = A.charAt(i);
if(mapa.containsKey(c)){
mapa.put(c, mapa.get(c) +1);
} else {
mapa.put(c, 1);
}
}
for(int i = 0; i < B.length(); i++){
char c = B.charAt(i);
if(!mapa.containsKey(c)){
return false;
} else {
mapa.put(c, mapa.get(c)-1);
if(mapa.get(c) < 0){
return false;
}
}
}
return true;
}
}