Leetcode-1528- rearrange string - hash table - string

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Note：

Open a hash table and record the letters corresponding to each number , And then from 0 Start restoring the string ,O(N) Complexity

The code is as follows ：

class Solution {
    
public:
    string restoreString(string s, vector<int>& indices) {
    
        unordered_map<int, char> hash;
        string ans;
        for(int i = 0; i < indices.size(); i ++)
            hash[indices[i]] = s[i];
        for(int i = 0; i < indices.size(); i ++)
            ans += hash[i];
        return ans;
    }
};