383. Ransom Note


Given
 an 
arbitrary
 ransom
 note
 string 
and 
another 
string 
containing 
letters from
 all 
the 
magazines,
 write 
a 
function 
that 
will 
return 
true 
if 
the 
ransom 
 note 
can 
be 
constructed 
from 
the 
magazines ; 
otherwise, 
it 
will 
return 
false. 



Each 
letter
 in
 the
 magazine 
string 
can
 only 
be
 used 
once
 in
 your 
ransom
 note.

Note:
You may assume that both strings contain only lowercase letters.

canConstruct("a", "b") -> false
canConstruct("aa", "ab") -> false
canConstruct("aa", "aab") -> true
代码如下：

 public class Solution {
     public boolean canConstruct(String ransomNote, String magazine) {
         if(ransomNote.length()<=magazine.length())
         {
             int i=0;
             while(i<ransomNote.length())
             {
                 int index=magazine.indexOf(ransomNote.charAt(i));
                 if(index!=-1)
                 {
                    magazine= magazine.replaceFirst(magazine.substring(index,index+1),"");
                     i++;
                 }
                 else return false;
             }
         }
         else return false;

         return true;
     }
 }