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#include "aoc.h"
namespace aoc2015 {
char* md5sum(char* s) {
static char md5[64] = {0};
uint8_t* x = md5String(s);
memset(md5, 0x0, 64);
for (auto i = 0; i < 16; i++) {
sprintf(md5 + i * 2, "%02x", x[i]);
}
return md5;
}
int lead_zeros(char* s) {
char* p = s;
int total = 0;
while (*p != '\0') {
if (*p == '0') {
total += 1;
p++;
}
else {
break;
}
}
return total;
}
int day4(const char* secret, int target) {
char buf[128] = {0};
int len = strlen(secret);
memcpy(buf, secret, len);
int i = 1;
while (i < INT32_MAX) {
sprintf(buf+len, "%d", i);
if (lead_zeros(md5sum(buf)) >= target) {
break;
}
i++;
}
return i;
}
} // namespace aoc2015
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