LeetCode 383 Ransom Note

Problem:

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.

You may assume that both strings contain only lowercase letters.

canConstruct("a", "b") -> false canConstruct("aa", "ab") -> false canConstruct("aa", "aab") -> true

Summary:

 给出两个字符串r，m，判断r串能否由m串组成。即r串中的所有字母包含在m串中即可。

Analysis:

Hash表

1 class Solution { 2 public: 3 bool canConstruct(string ransomNote, string magazine) { 4 int magChar[26] = {0}; 5 int len = magazine.size(); 6 for (int i = 0; i < len; i++) { 7 magChar[magazine[i] - 'a']++; 8 } 9 10 len = ransomNote.size(); 11 for (int i = 0; i < len; i++) { 12 if (--magChar[ransomNote[i] - 'a'] < 0) { 13 return false; 14 } 15 } 16 17 return true; 18 } 19 };

转载于:https://www.cnblogs.com/VickyWang/p/5998925.html

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