leetcode/algorithms/cpp/ransomNote/RansomNote.cpp at master · qufengbin/leetcode

38 lines (36 loc) · 1.34 KB

// Source : https://leetcode.com/problems/ransom-note/

// Author : Hao Chen

// Date : 2016-08-24

/***************************************************************************************

*  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

***************************************************************************************/

class Solution {

public:

bool canConstruct(string ransomNote, string magazine) {

unordered_map<char, int> m;

for(int i=0; i<magazine.size(); i++) {

m[magazine[i]]++;

}

for (int i=0; i<ransomNote.size(); i++) {

char c = ransomNote[i];

if (m[c] <=0 ) return false;

m[c]--;

}

return true;

}

};

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