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
|
#include <iostream>
#include <fstream>
#include <vector>
#include <map>
long bin_to_int (std::string bin) {
long num = 0, exp = 1;
for (int i=bin.size()-1; i>=0; i--) {
int bit = bin[i] == '1' ? 1 : 0;
num += bit * exp;
exp *= 2;
}
return num;
}
std::string hex_to_bin (std::string hex) {
std::map<char, std::string> convert {
{ '0', "0000" }, { '1', "0001" }, { '2', "0010" }, { '3', "0011" },
{ '4', "0100" }, { '5', "0101" }, { '6', "0110" }, { '7', "0111" },
{ '8', "1000" }, { '9', "1001" }, { 'A', "1010" }, { 'B', "1011" },
{ 'C', "1100" }, { 'D', "1101" }, { 'E', "1110" }, { 'F', "1111" },
};
std::string bin;
for (char c : hex) { bin += convert[c]; }
return bin;
}
long parse_literal (std::string raw) {
std::string lit;
for (int i=0; i<raw.size(); i++) {
auto group = raw.substr(i*5, 5);
lit += group.substr(1, 4);
if (group[0] == '0') break;
}
return bin_to_int(lit);
}
class Packet {
public:
Packet () { }
int version;
int id;
long literal;
std::vector<Packet> packets;
int parse (std::string raw) {
int parsed = 0;
version = bin_to_int(raw.substr(0, 3));
id = bin_to_int(raw.substr(3, 3));
parsed += 6;
if (id == 4) {
std::string lit;
for (int i=0; ; i++) {
auto group = raw.substr(parsed, 5);
parsed += 5;
lit += group.substr(1, 4);
if (group[0] == '0') break;
}
literal = bin_to_int(lit);
} else {
parsed += 1;
if (raw[6] == '0') {
int len = bin_to_int(raw.substr(7, 15));
parsed += 15;
int local = 0;
while (local < len) {
Packet pack;
int size = pack.parse(raw.substr(parsed));
local += size;
parsed += size;
packets.push_back(pack);
}
} else {
int len = bin_to_int(raw.substr(7, 11));
parsed += 11;
int local = 0;
while (local < len) {
Packet pack;
int size = pack.parse(raw.substr(parsed));
local += 1;
parsed += size;
packets.push_back(pack);
}
}
}
return parsed;
}
int sum_version () {
int s = version;
for (Packet pack : packets) { s += pack.sum_version(); }
return s;
}
long eval () {
long res = 0;
if (id == 4) {
res = literal;
}
else if (id == 5) {
res = packets[0].eval() > packets[1].eval() ? 1 : 0;
}
else if (id == 6) {
res = packets[0].eval() < packets[1].eval() ? 1 : 0;
}
else if (id == 7) {
res = packets[0].eval() == packets[1].eval() ? 1 : 0;
}
else {
bool first = true;
for (Packet pack : packets) {
if (first) {
res = pack.eval();
first = false;
continue;
}
if (id == 0) res += pack.eval();
if (id == 1) res *= pack.eval();
if (id == 2) res = std::min(res, pack.eval());
if (id == 3) res = std::max(res, pack.eval());
}
}
return res;
}
};
int main (int argc, char *argv[]) {
std::string raw;
if (std::string({ argv[1] }) == "-i") {
raw = std::string({ argv[2] });
} else {
std::getline(std::ifstream(argv[1]), raw, '\0');
}
std::cout << raw << std::endl;
std::string bin = hex_to_bin(raw);
std::cout << bin << std::endl;
Packet packet;
packet.parse(bin);
std::cout << "version sum: " << packet.sum_version() << std::endl;
std::cout << "eval to: " << packet.eval() << std::endl;
return 0;
}
|
