lc1306

class Solution {
public:
    bool canReach(vector<int>& arr, int start) {
        unordered_set<int> visited;
        queue<int> q;
        
        visited.insert(start);
        q.push(start);
        
        while(!q.empty()) {
            int tempIndx = q.front();
            q.pop();
            
            if(arr[tempIndx] == 0)
                return true;
            int leftIndx = tempIndx - arr[tempIndx];
            int rightIndx = tempIndx + arr[tempIndx];
            if(leftIndx >= 0 && !visited.count(leftIndx)) {
                q.push(leftIndx);
                visited.insert(leftIndx);
            }
            if(rightIndx < arr.size() && !visited.count(rightIndx)) {
                q.push(rightIndx);
                visited.insert(rightIndx);
            }
                
        }
        return false;
        
    }
};