Leetcode-567 Permutation in String(字符串的排列)

class Solution
{
    public:
        bool checkInclusion(string s1, string s2)
        {
            if(s2.size()<s1.size())
                return false;
            int length = s1.size();
            int hashForA[29] {0};
            bool result = false;
            
            for(int i = 0;i < length;i ++)
            {
                hashForA[s1[i]-'a'] ++;
            }
            for(int i = 0;i < s2.size()-length+1;i ++)
            {
                int hash[29] {0};
                for(int j = 0;j < length;j ++)
                {
                    hash[s2[i+j]-'a'] ++;
                }
                int k;
                for(k = 0;k < 28;k ++)
                {
                    if(hash[k] != hashForA[k])
                        break;
                }
                if(k == 28)
                    result = true;
            }
            return result;
        }
};