-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathStack341.java
More file actions
66 lines (57 loc) · 2.02 KB
/
Stack341.java
File metadata and controls
66 lines (57 loc) · 2.02 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
package stack;
import java.util.Iterator;
import java.util.List;
import java.util.Stack;
public class Stack341 {
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> {
Stack<NestedInteger> stack;
List<NestedInteger> nestedList;
public NestedIterator(List<NestedInteger> nestedList) {
stack = new Stack<>();
this.nestedList = nestedList;
}
@Override
public Integer next() {
return getNext().getInteger();
}
public NestedInteger getNext() {
List<NestedInteger> temp;
if (stack.isEmpty() && !nestedList.isEmpty()) {
stack.push(nestedList.remove(0));
}
while (!stack.peek().isInteger()){
temp = stack.peek().getList();
if (temp.size() > 0) {
stack.push(temp.remove(0));
} else {
stack.pop();
}
if (stack.isEmpty() && !nestedList.isEmpty()) {
stack.push(nestedList.remove(0));
}
}
if (stack.isEmpty()) return null;
return stack.pop();
}
@Override
public boolean hasNext() {
NestedInteger nestedInteger = this.getNext();
if (nestedInteger != null) {
return false;
} else {
stack.push(nestedInteger);
return true;
}
}
}
}