DI String Match

A permutation perm of n + 1 integers of all the integers in the range [0, n] can be represented as a string s of length n where:
s[i] == 'I' if perm[i] < perm[i + 1], and
s[i] == 'D' if perm[i] > perm[i + 1].
Given a string s, reconstruct the permutation perm and return it. If there are multiple valid permutations perm, return any of them.

Example 1:
Input: s = "IDID"
Output: [0,4,1,3,2]

Example 2:
Input: s = "III"
Output: [0,1,2,3]

Example 3:
Input: s = "DDI"
Output: [3,2,0,1]
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// tc=O(n) sc=O(n)
class Solution {
public:
    vector<int> diStringMatch(string s) {
        int n=s.size();
        vector<int>res;
        int i=0, j=n;
        int k=0;
        while(k<n){
            if(s[k]=='I'){
                res.push_back(i);
                i++;
            }
            else{
                res.push_back(j);
                j--;
            }
            k++;
        }
        res.push_back(i);
        return res;
    }
};