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#include "aoc.h"
#include <vector>
namespace aoc2019 {
int get_number(const char** pp) {
const char* p = *pp;
int d{0};
while (*p >= '0' && *p <= '9') {
d = d * 10 + *p - '0';
p++;
}
*pp = p;
return d;
}
static void run(size_t i, std::vector<int>& codes) {
// printf("execute %d at %zu\n", codes[i], i);
switch (codes[i]) {
case 1:
codes[codes[i + 3]] = codes[codes[i + 1]] + codes[codes[i + 2]];
run(i + 4, codes);
break;
case 2:
codes[codes[i + 3]] = codes[codes[i + 1]] * codes[codes[i + 2]];
run(i + 4, codes);
break;
case 99:
break;
default:
printf("UNKNOWN CODE %d at %zu\n", codes[i], i);
break;
}
}
int test(int n, int v, std::vector<int> codes) {
codes[1] = n;
codes[2] = v;
run(0, codes);
return codes[0];
}
int test(int target, const std::vector<int>& codes) {
for (int n = 0; n <= 99; n++) {
for (int v = 0; v <= 99; v++) {
if (target == test(n, v, codes)) {
return n * 100 + v;
}
}
}
return 0;
}
std::pair<int, int> day2(line_view file) {
std::vector<int> optcodes;
const char* p = file.line;
while (p < file.line + file.length) {
if (*p >= '0' && *p <= '9') {
optcodes.emplace_back(get_number(&p));
}
p++;
}
return {test(12, 2, optcodes), test(19690720, optcodes)};
}
} // namespace aoc2019
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