forked from aishraj/JavaScript-Interview-Questions
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy path009.js
More file actions
166 lines (144 loc) · 3.61 KB
/
Copy path009.js
File metadata and controls
166 lines (144 loc) · 3.61 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
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
/*
* <!--
* This program is distributed under
* the terms of the MIT license.
* Please see the LICENSE file for details.
* -->
*/
/*
* In the game of Towers of Hanoi, you have 3 rods and N disks of different
* sizes which can slide onto any tower. The puzzle starts with disks sorted in
* ascending order of size from top to bottom (each disk sits on top of an even
* larger disk) with the following constraints.
* 1. Only one disk can be moved at a time.
* 2. A disk is slid off the top of one rod onto the next rod.
* 3. A disk can only be placed on top of a larger disk.
*
* Write a program to move the disks from the first rod to the last.
*/
/*____________________________________________________________________________*/
/**
* @class {public} Tower
*
* A data structure for a Hanoi tower.
*/
/**
* @constructor Tower.Tower
*
* Creates a new tower.
*
* @param {Integer} i - the index of the tower.
*/
function Tower(i) {
this.disks = [];
this.index = i;
}
var tp = Tower.prototype;
/**
* @function {public} Tower.add
*
* Add a disk to the tower.
*
* @param {Integer} d - the size of the disk.
*/
tp.add = function(d) {
if (this.disks.length === 0 && this.disks[0] <= d) {
return;
}
this.disks.push(d);
};
/**
* @function {public} Tower.moveTopTo
*
* Moves the top disk of this tower, to another tower.
*
* @param {Tower} anotherTower - the tower to move to.
*/
tp.moveTopTo = function(anotherTower) {
var top = this.disks.pop();
anotherTower.add(top);
console.log([
'Moved disk ', top, ' from ', this.index, ' to ', anotherTower.index
].join(''));
};
/**
* @function {public} Tower.print
*
* Prints the contents of the tower.
*/
tp.print = function() {
console.log(['Contents of tower', this.index].join(''));
var i = 0;
var buffer = [];
for (i = this.disks.length - 1; i >= 0; i--) {
buffer.push(' ');
buffer.push(this.disks[i]);
}
console.log(buffer.join(''));
}
/**
* @function {public} Tower.moveDisks
*
* Moves n disks from ths tower to destination tower using a buffer tower.
*
* @param {Integer} n - the number of disks to move.
* @param {Tower} destination - the destination `Tower` to move to.
* @param {Tower} buffer - intermediate buffer `Tower`.
*/
tp.moveDisks = function(n, destination, buffer) {
if (n === 0) {
return;
}
this.moveDisks(n - 1, buffer, destination);
this.moveTopTo(destination);
buffer.moveDisks(n-1, destination, this);
};
(function main() {
var n = 5;
var towers = [];
var i = 0;
for (i = 0; i < 3; i++) {
towers[i] = new Tower(i);
}
for (i = n -1; i >= 0; i--) {
towers[0].add(i);
}
towers[0].moveDisks(n, towers[2], towers[1]);
towers[2].print();
}());
/*
Output: ($ /usr/bin/node 009.js)
Moved disk 0 from 0 to 2
Moved disk 1 from 0 to 1
Moved disk 0 from 2 to 1
Moved disk 2 from 0 to 2
Moved disk 0 from 1 to 0
Moved disk 1 from 1 to 2
Moved disk 0 from 0 to 2
Moved disk 3 from 0 to 1
Moved disk 0 from 2 to 1
Moved disk 1 from 2 to 0
Moved disk 0 from 1 to 0
Moved disk 2 from 2 to 1
Moved disk 0 from 0 to 2
Moved disk 1 from 0 to 1
Moved disk 0 from 2 to 1
Moved disk 4 from 0 to 2
Moved disk 0 from 1 to 0
Moved disk 1 from 1 to 2
Moved disk 0 from 0 to 2
Moved disk 2 from 1 to 0
Moved disk 0 from 2 to 1
Moved disk 1 from 2 to 0
Moved disk 0 from 1 to 0
Moved disk 3 from 1 to 2
Moved disk 0 from 0 to 2
Moved disk 1 from 0 to 1
Moved disk 0 from 2 to 1
Moved disk 2 from 0 to 2
Moved disk 0 from 1 to 0
Moved disk 1 from 1 to 2
Moved disk 0 from 0 to 2
Contents of tower2
0 1 2 3 4
*/