|
6 | 6 | */ |
7 | 7 |
|
8 | 8 | class TwoStacks { |
9 | | - constructor() { |
| 9 | + constructor(capacity) { |
10 | 10 | this.data = []; |
11 | | - this.top1 = null; |
12 | | - this.top2 = null; |
13 | | - this.stack1Count = 0; |
14 | | - this.stack2Count = 0; |
| 11 | + this.capacity = capacity; |
| 12 | + this.top1 = -1; |
| 13 | + this.top2 = capacity; |
15 | 14 | } |
16 | 15 |
|
17 | 16 | push1(value) { |
18 | | - if (!this.data.length) { |
19 | | - this.data.push(value); |
20 | | - this.top1 = value; |
21 | | - this.stack1Count += 1; |
22 | | - } else { |
23 | | - const arr = []; |
24 | | - for (let i = 0; i < this.stack1Count; i += 1) { |
25 | | - arr.push(this.data[i]); |
26 | | - } |
27 | | - arr.push(value); |
28 | | - for (let i = this.stack1Count; i < this.data.length; i += 1) { |
29 | | - arr.push(this.data[i]); |
30 | | - } |
31 | | - this.data = arr; |
32 | | - this.top1 = value; |
33 | | - this.stack1Count += 1; |
| 17 | + if (this.top1 === -1 || this.top1 < this.top2 - 1) { |
| 18 | + this.top1 += 1; |
| 19 | + this.data[this.top1] = value; |
| 20 | + return; |
34 | 21 | } |
| 22 | + throw new Error('Overflow'); |
35 | 23 | } |
36 | 24 |
|
37 | 25 | push2(value) { |
38 | | - if (!this.data.length) { |
39 | | - this.data.push(value); |
40 | | - this.top2 = value; |
41 | | - this.stack2Count += 1; |
42 | | - } else { |
43 | | - const arr = []; |
44 | | - for (let i = 0; i < this.stack1Count; i += 1) { |
45 | | - arr.push(this.data[i]); |
46 | | - } |
47 | | - arr.push(value); |
48 | | - |
49 | | - for (let i = this.stack1Count; i < this.data.length; i += 1) { |
50 | | - arr.push(this.data[i]); |
51 | | - } |
52 | | - this.data = arr; |
53 | | - this.top2 = value; |
54 | | - this.stack2Count += 1; |
| 26 | + if (this.top2 <= this.capacity && this.top2 > this.top1) { |
| 27 | + this.data[this.top2] = value; |
| 28 | + this.top2 -= 1; |
| 29 | + return; |
55 | 30 | } |
| 31 | + throw new Error('Overflow'); |
56 | 32 | } |
57 | 33 |
|
58 | | - pop1() { |
59 | | - if (!this.top1) { |
60 | | - return null; |
61 | | - } |
62 | | - |
63 | | - const indexOfTop1 = this.data.indexOf(this.top1); |
64 | | - const arr = []; |
| 34 | + pop1() {} |
65 | 35 |
|
66 | | - delete this.data[indexOfTop1]; |
67 | | - |
68 | | - this.data.forEach(el => arr.push(el)); |
69 | | - |
70 | | - const oldTop = this.top1; |
71 | | - this.top1 = this.data[indexOfTop1 - 1]; |
72 | | - this.data = arr; |
73 | | - return oldTop; |
74 | | - } |
75 | | - |
76 | | - pop2() { |
77 | | - return this.data.pop(); |
78 | | - } |
| 36 | + pop2() {} |
79 | 37 | } |
80 | 38 |
|
81 | 39 | module.exports = TwoStacks; |
82 | 40 |
|
83 | 41 | /** Test cases */ |
84 | 42 |
|
85 | | -/* |
86 | | - |
87 | | -const s = new TwoStacks(); |
| 43 | +const s = new TwoStacks(3); |
88 | 44 |
|
| 45 | +s.push1('a'); |
89 | 46 | console.log(s.data); |
90 | 47 |
|
91 | | -s.push1(5); |
92 | | -s.push1(4); |
| 48 | +s.push2('a2'); |
93 | 49 | console.log(s.data); |
94 | 50 |
|
95 | | - |
96 | | -s.push2(2) |
97 | | -s.push2(1); |
| 51 | +s.push1('b'); |
98 | 52 | console.log(s.data); |
99 | 53 |
|
100 | | -s.push1(14); |
| 54 | +s.push2('b2'); |
101 | 55 | console.log(s.data); |
102 | | -console.log(s.top1); |
103 | 56 |
|
104 | | -console.log(s.pop1()) |
| 57 | +s.push2('b3'); |
105 | 58 | console.log(s.data); |
106 | | - |
107 | | -console.log(s.pop1()) |
108 | | -console.log(s.data); |
109 | | - |
110 | | -console.log(s.pop2()) |
111 | | -console.log(s.data); |
112 | | - |
113 | | -console.log(s.pop2()) |
114 | | -console.log(s.data); |
115 | | - |
116 | | -console.log(s.pop2()) |
117 | | -console.log(s.data); |
118 | | - |
119 | | -console.log(s.pop1()) |
120 | | -console.log(s.data); |
121 | | - |
122 | | -*/ |
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