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#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#define INPUT_LEN 1000
#define SEARCH_LEN 25
uint64_t min_uint64(const uint64_t *start, const uint64_t *stop)
{
uint64_t min = *start;
while (++start <= stop) {
if (*start < min) {
min = *start;
}
}
return min;
}
uint64_t max_uint64(const uint64_t *start, const uint64_t *stop)
{
uint64_t max = *start;
while (++start <= stop) {
if (*start > max) {
max = *start;
}
}
return max;
}
bool has_sum(uint64_t *cur_num)
{
uint64_t search = *cur_num;
uint64_t *p1 = cur_num - SEARCH_LEN;
do {
if (*p1 >= search)
{
continue;
}
uint64_t *p2 = cur_num - SEARCH_LEN;
do {
if (*p1 + *p2 == search) {
return true;
}
} while (++p2 < cur_num);
} while (++p1 < cur_num);
return false;
}
int exe_program(const char *filename)
{
FILE *file = fopen(filename, "r");
// Include space for newline and string terminator
char buffer[24] = { 0 };
uint64_t nums[INPUT_LEN] = { 0 };
size_t num_size = 0;
while (fgets(buffer, 24, file)) {
nums[num_size++] = strtoull(buffer, NULL, 10);
}
fclose(file);
uint64_t *cur_num = nums + SEARCH_LEN;
uint64_t search = -1;
do {
if (!has_sum(cur_num)) {
search = *cur_num;
break;
}
} while (++cur_num < nums + num_size);
cur_num = nums;
do {
uint64_t sum = 0;
uint64_t *p1 = cur_num;
do {
sum += *p1;
} while (++p1 < nums + num_size && sum < search);
if (sum == search) {
return min_uint64(cur_num, p1) + max_uint64(cur_num, p1);
}
} while (++cur_num < nums + num_size);
return -1;
}
int main(int argc, char *argv[])
{
printf("%i\n", exe_program(argv[argc - 1]));
}
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