-
Notifications
You must be signed in to change notification settings - Fork 0
/
tree.zig
212 lines (168 loc) · 5.64 KB
/
tree.zig
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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
const std = @import("std");
const utils = @import("utils.zig");
pub const TreeNode = struct {
// char
value: u8,
probability: i32,
left_child: ?*const TreeNode,
right_child: ?*const TreeNode,
};
pub fn pre_order_traversal(node: TreeNode, arr: []u8, arrPointer: *usize) void {
arr[arrPointer.*] = node.value;
arrPointer.* += 1;
if (node.left_child) |left| {
pre_order_traversal(left.*, arr, arrPointer);
}
if (node.right_child) |right| {
pre_order_traversal(right.*, arr, arrPointer);
}
}
pub fn build_simple_tree(allocator: std.mem.Allocator, preOrder: []u8, index: *usize) !*TreeNode {
if (preOrder[index.*] != 0) {
var node = try allocator.create(TreeNode);
node.* = .{
.value = preOrder[index.*],
.probability = 0,
.left_child = null,
.right_child = null,
};
index.* += 1;
return node;
}
var node = try allocator.create(TreeNode);
node.* = .{
.value = 0,
.probability = 0,
.left_child = null,
.right_child = null,
};
index.* += 1;
node.*.left_child = try build_simple_tree(allocator, preOrder, index);
node.*.right_child = try build_simple_tree(allocator, preOrder, index);
return node;
}
pub fn walk(node: TreeNode, search: u16, path: u16) ?u16 {
var myPath = path;
if (node.value == search) {
return myPath;
}
if (node.left_child) |left| {
myPath = myPath << 1;
const ret = walk(left.*, search, myPath);
if (ret != null) {
return ret;
}
myPath = myPath >> 1;
}
if (node.right_child) |right| {
myPath = myPath << 1;
myPath += 1;
var ret = walk(right.*, search, myPath);
if (ret != null) {
return ret;
}
myPath -= 1;
myPath = myPath >> 1;
}
return null;
}
const expect = std.testing.expect;
const expectEqual = std.testing.expectEqual;
test "Walk function" {
const first = TreeNode{
.value = 1,
.probability = 0,
.left_child = null,
.right_child = null,
};
const second = TreeNode{
.value = 2,
.probability = 0,
.left_child = null,
.right_child = null,
};
const third = TreeNode{
.value = 3,
.probability = 0,
.left_child = null,
.right_child = null,
};
const forth = TreeNode{
.value = 4,
.probability = 0,
.left_child = null,
.right_child = null,
};
const firstParent = TreeNode{
.value = 0,
.probability = 0,
.left_child = &first,
.right_child = &second,
};
const secondParent = TreeNode{
.value = 0,
.probability = 0,
.left_child = &third,
.right_child = &forth,
};
const root = TreeNode{
.value = 0,
.probability = 0,
.left_child = &firstParent,
.right_child = &secondParent,
};
const page_alloc = std.heap.page_allocator;
var preOrderArr = try page_alloc.alloc(u8, 7);
var preOrderPointer: usize = 0;
pre_order_traversal(root, preOrderArr, &preOrderPointer);
// Important to start with 1. otherwise bitshifting on 0s would do nothing.
try expectEqual(@as(u16, 0b00000100), walk(root, 1, 1).?);
try expectEqual(@as(u16, 0b00000101), walk(root, 2, 1).?);
try expectEqual(@as(u16, 0b00000110), walk(root, 3, 1).?);
try expectEqual(@as(u16, 0b00000111), walk(root, 4, 1).?);
var bitmask: u64 = 0;
var bitmask_used: u16 = 0;
var pattern = walk(root, 1, 1).?;
// Minus 1 because of the beginning 1.
var pattern_used = utils.count_bits_used(pattern) - 1;
try expectEqual(@as(u16, 2), pattern_used);
var clean_pattern = pattern - std.math.pow(u8, 2, pattern_used);
try expectEqual(@as(u16, 0b00000000), clean_pattern);
var shifted_bits: u64 = @as(u64, clean_pattern);
shifted_bits = shifted_bits << @truncate(u6, (64 - (bitmask_used + pattern_used)));
bitmask |= shifted_bits;
bitmask_used += pattern_used;
var test_counter: u64 = 0;
try expectEqual(@as(u16, 2), bitmask_used);
try expectEqual(test_counter, bitmask);
// ------------
pattern = walk(root, 4, 1).?;
pattern_used = utils.count_bits_used(pattern) - 1;
clean_pattern = pattern - std.math.pow(u8, 2, pattern_used);
try expectEqual(@as(u16, 2), pattern_used);
try expectEqual(@as(u16, 0b00000111), pattern);
try expectEqual(@as(u16, 0b00000011), clean_pattern);
try expectEqual(@as(u16, 2), pattern_used);
shifted_bits = @as(u64, clean_pattern);
shifted_bits = shifted_bits << @truncate(u6, (64 - (bitmask_used + pattern_used)));
bitmask |= shifted_bits;
bitmask_used += pattern_used;
test_counter += std.math.pow(u64, 2, 61) + std.math.pow(u64, 2, 60);
try expectEqual(@as(u16, 4), bitmask_used);
try expectEqual(@as(u64, test_counter), bitmask);
// ----------
pattern = walk(root, 3, 1).?;
pattern_used = utils.count_bits_used(pattern) - 1;
clean_pattern = pattern - std.math.pow(u8, 2, pattern_used);
try expectEqual(@as(u16, 2), pattern_used);
try expectEqual(@as(u16, 0b00000110), pattern);
try expectEqual(@as(u16, 0b00000010), clean_pattern);
try expectEqual(@as(u16, 2), pattern_used);
shifted_bits = @as(u64, clean_pattern);
shifted_bits = shifted_bits << @truncate(u6, (64 - (bitmask_used + pattern_used)));
bitmask |= shifted_bits;
bitmask_used += pattern_used;
test_counter += std.math.pow(u64, 2, 59);
try expectEqual(@as(u16, 6), bitmask_used);
try expectEqual(test_counter, bitmask);
}