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#include "aoc.h"
#include <vector>
namespace aoc2017 {
int get_number(line_view lv) {
const char* p = lv.line;
int sign = 1;
if (*p == '-') {
sign = -1;
p++;
}
int d{0};
while (*p >= '0' && *p <= '9') {
d = d * 10 + *p - '0';
p++;
}
return d * sign;
}
void follow(int i, std::vector<int>& ins, int* steps) {
// printf("%d\n", ins[i]);
int x = ins[i];
int n = i + x;
if (n >= 0 && n < int(ins.size())) {
// ins[i] += x >= 3 ? -1 : 1; part2
ins[i] += 1;
*steps += 1;
follow(n, ins, steps);
}
}
int day5(line_view file) {
std::vector<int> ins;
per_line(file, [&ins](line_view lv) {
ins.emplace_back(get_number(lv));
return true;
});
int steps{0};
follow(0, ins, &steps);
return steps + 1;
}
} // namespace aoc2017
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