Java - Easy to understand solution faster than 65% of other solutions


  • 0
    T

    Very easy to understand. Use this if you do not understand other solutions that are better efficient ;) .
    Let me know if you have any questions. Happy to help :)

    /**
     * // This is the interface that allows for creating nested lists.
     * // You should not implement it, or speculate about its implementation
     * public interface NestedInteger {
     *
     *     // @return true if this NestedInteger holds a single integer, rather than a nested list.
     *     public boolean isInteger();
     *
     *     // @return the single integer that this NestedInteger holds, if it holds a single integer
     *     // Return null if this NestedInteger holds a nested list
     *     public Integer getInteger();
     *
     *     // @return the nested list that this NestedInteger holds, if it holds a nested list
     *     // Return null if this NestedInteger holds a single integer
     *     public List<NestedInteger> getList();
     * }
     */
    public class NestedIterator implements Iterator<Integer> {
        List<Integer> list;Iterator<Integer> it;
        public NestedIterator(List<NestedInteger> nestedList) {
            list = new ArrayList<>();
            helper(nestedList);
            it = list.iterator();
        }
        
        private void helper(List<NestedInteger> nestedList){
            
            for(int i=0;i<nestedList.size();i++){
                NestedInteger j = nestedList.get(i);
                if(j.isInteger()){
                    list.add(j.getInteger());
                }else{
                    helper(j.getList());
                }
            }
        }
    
        @Override
        public Integer next() {
            return it.next();
        }
    
        @Override
        public boolean hasNext() {
            return it.hasNext();
        }
    }
    
    /**
     * Your NestedIterator object will be instantiated and called as such:
     * NestedIterator i = new NestedIterator(nestedList);
     * while (i.hasNext()) v[f()] = i.next();
     */
    

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