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#include "aoc.h"
#include <unordered_map>
namespace aoc2017 {
int largest(const std::unordered_map<line_view, int>& rs) {
int max{INT32_MIN};
for (auto& kv : rs) {
if (kv.second > max) {
max = kv.second;
}
}
return max;
}
static void get_number(const char** pp, int* d) {
const char* p = *pp;
*d = 0;
int sign = 1;
if (*p == '-') {
sign = -1;
p++;
}
while (*p >= '0' && *p <= '9') {
*d = *d * 10 + *p - '0';
p++;
}
*d = *d * sign;
*pp = p;
}
line_view get_label(const char** pp) {
const char* p = *pp;
const char* p1 = p;
while (*p != ' ') {
p++;
}
*pp = p;
return {p1, p};
}
static int inc(int x, int i) { return x + i; }
static int dec(int x, int i) { return x - i; }
static bool condition_met(line_view cond, int x, int i) {
if (*cond.line == '=') {
return x == i;
}
if (*cond.line == '!') {
return x != i;
}
bool bs[] = {x > i, x < i, x >= i, x <= i};
return bs[size_t(*cond.line == '<') + (cond.length & 2)];
}
typedef int (*op)(int, int);
std::pair<int, int> day8(line_view file) {
std::unordered_map<line_view, int> registers;
int max{INT32_MIN};
per_line(file, [®isters, &max](line_view lv) {
const char* p = lv.line;
line_view v1 = get_label(&p);
op f = p[1] == 'd' ? dec : inc;
p += 5;
int d1{0};
get_number(&p, &d1);
p += 4;
line_view v2 = get_label(&p);
p += 1;
line_view condition = get_label(&p);
p += 1;
int d2{0};
get_number(&p, &d2);
if (condition_met(condition, registers[v2], d2)) {
registers[v1] = f(registers[v1], d1);
if (registers[v1] > max) {
max = registers[v1];
}
}
return true;
});
return {largest(registers), max};
}
} // namespace aoc2017
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