Cracking the Coding Interview, 4 Edition - 150 Programming Interview Questions and Solutions

Solutions to Chapter 3 | Stacks and Queues
33 stack.push(v);
34 }
35 return removed_item;
36 }
37 }
38
39 public class Stack {
40 private int capacity;
41 public Node top, bottom;
42 public int size = 0;
43
44 public Stack(int capacity) { this.capacity = capacity; }
45 public boolean isAtCapacity() { return capacity == size; }
46
47 public void join(Node above, Node below) {
48 if (below != null) below.above = above;
49 if (above != null) above.below = below;
50 }
51
52 public boolean push(int v) {
53 if (size >= capacity) return false;
54 size++;
55 Node n = new Node(v);
56 if (size == 1) bottom = n;
57 join(n, top);
58 top = n;
59 return true;
60 }
61
62 public int pop() {
63 Node t = top;
64 top = top.below;
65 size--;
66 return t.value;
67 }
68
69 public boolean isEmpty() { return size == 0; }
70 public int removeBottom() {
71 Node b = bottom;
72 bottom = bottom.above;
73 if (bottom != null) bottom.below = null;
74 size--;
75 return b.value;
76 }
77 }
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Cracking the Coding Interview | Data Structures