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#include "aoc.h"
#include <string.h>
#include <vector>
#include <functional>
namespace aoc2015 {
static int registers[2] = {0};
void execute(size_t i, const std::vector<line_view>& is);
void hlf(size_t i, const std::vector<line_view>& is, const char *p) {
int x = *p == 'a' ? 0 : 1;
registers[x] /= 2;
execute(i+1, is);
}
void tpl(size_t i, const std::vector<line_view>& is, const char *p) {
int x = *p == 'a' ? 0 : 1;
registers[x] *= 3;
execute(i+1, is);
}
void inc(size_t i, const std::vector<line_view>& is, const char *p) {
int x = *p == 'a' ? 0 : 1;
registers[x] += 1;
execute(i+1, is);
}
static int get_number(const char *p) {
int sign = *p == '+' ? 1 : -1;
p++;
int d{0};
while(*p <= '9' && *p >= '0') {
d = 10 * d + *p - '0';
p++;
}
d *= sign;
return d;
}
void jmp(size_t i, const std::vector<line_view>& is, const char *p) {
int d = get_number(p);
execute(i+d, is);
}
void jie(size_t i, const std::vector<line_view>& is, const char *p) {
int x = *p == 'a' ? 0 : 1;
p += 3;
int d = registers[x] % 2 == 0 ? get_number(p) : 1;
execute(i+d, is);
}
void jio(size_t i, const std::vector<line_view>& is, const char *p) {
int x = *p == 'a' ? 0 : 1;
p += 3;
int d = registers[x] == 1 ? get_number(p) : 1;
execute(i+d, is);
}
void execute(size_t i, const std::vector<line_view>& is) {
if (i >= is.size()) {
return;
}
line_view cmd = is[i];
const char* p = cmd.line;
struct {
const char* ins;
std::function<void(size_t, const std::vector<line_view>&, const char*)> f;
} cmds[] = {
{"hlf", hlf},
{"tpl", tpl},
{"inc", inc},
{"jmp", jmp},
{"jie", jie},
{"jio", jio},
};
for(auto& c : cmds) {
if (strncmp(p, c.ins, 3) == 0) {
c.f(i, is, p+4);
break;
}
}
}
std::pair<int, int> day23(line_view file) {
std::vector<line_view> is;
per_line(file, [&is](line_view lv){
is.push_back(lv);
return true;
});
execute(0, is);
int a1 = registers[1];
registers[0] = 1;
registers[1] = 0;
execute(0, is);
int a2 = registers[1];
return {a1, a2};
}
}
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