383. Ransom Note

class Solution {
public:
    bool canConstruct(string ransomNote, string magazine) 
    {
        int n = ransomNote.length(), m = magazine.length();
        sort(ransomNote.begin(), ransomNote.end());
        sort(magazine.begin(), magazine.end());
        int i=0, j=0, a=0;
        if(n>m)
        {
           return false;
        }

        else
        {
            while(i<n && j<m)
            {
                if(ransomNote[i]==magazine[j])
                {
                    a=1;
                    i++;
                    j++;
                }
                else if(ransomNote[i] > magazine[i])
                {
                    j++;
                }

                else
                {
                    a=0; 
                    break;
                }
            }
        }

        if(a==1 && i==n)  return true;

        return false;
    }
};