minJumps

class Solution {
public:
    int minJumps(vector<int>& arr) {
        int n = arr.size();
        unordered_map<int, vector<int>> idx_of_same_val;
        for(int i = 0; i < n; i++){
            idx_of_same_val[arr[i]].push_back(i);
        }
        queue<int> q;
        vector<bool> visited(n, false);
        q.push(0);
        visited[0] = true;
        int steps = 0;
        while(!q.empty()){
            int qsize = q.size();
            for(int i = 0; i < qsize; i++){
                int t = q.front();
                q.pop();
                if(t == n - 1) return steps;
                if(t + 1 < n && !visited[t + 1]){
                    q.push(t + 1);
                    visited[t + 1] = true;
                }
                if(t - 1 >= 0 && !visited[t - 1]){
                    q.push( t - 1 );
                    visited[t - 1] = true;
                }
                for(int j = idx_of_same_val[arr[t]].size() - 1; j >= 0 ; j--){
                    if(idx_of_same_val[arr[t]][j] != t && !visited[idx_of_same_val[arr[t]][j]]){
                        q.push(idx_of_same_val[arr[t]][j]);
                        visited[idx_of_same_val[arr[t]][j]] = true;
                    }
                }
            }
            steps += 1;
        }
        return steps;
    }
};