160 lines
3.0 KiB
C
160 lines
3.0 KiB
C
#include <math.h>
|
|
#include <stdbool.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#ifdef __PROGTEST__
|
|
#define debug(...) ((void)0)
|
|
#else
|
|
#define debug(fmt, ...) \
|
|
printf("[DEBUG %s:%d %s()] " fmt "\n", __FILE__, __LINE__, \
|
|
__func__, ##__VA_ARGS__)
|
|
#endif
|
|
|
|
typedef long long int lli;
|
|
typedef long double ld;
|
|
|
|
typedef struct rails_t {
|
|
lli r1;
|
|
lli r2;
|
|
lli d;
|
|
} rails_t;
|
|
|
|
typedef struct eea_gcd_t {
|
|
lli g;
|
|
lli x;
|
|
lli y;
|
|
} eea_gcd_t;
|
|
|
|
int invalid_input() {
|
|
printf("Nespravny vstup.\n");
|
|
return EXIT_FAILURE;
|
|
}
|
|
|
|
eea_gcd_t extended_euclidian_gcd(lli a, lli b) {
|
|
if (a == 0) {
|
|
eea_gcd_t res;
|
|
res.g = b;
|
|
res.x = 0;
|
|
res.y = 1;
|
|
return res;
|
|
}
|
|
|
|
eea_gcd_t res = extended_euclidian_gcd(b % a, a);
|
|
|
|
lli x = res.y - (b / a) * res.x;
|
|
lli y = res.x;
|
|
|
|
res.x = x;
|
|
res.y = y;
|
|
|
|
return res;
|
|
}
|
|
|
|
|
|
lli find_solutions(rails_t rails, bool verbose) {
|
|
lli variants = 0;
|
|
|
|
if (rails.d == 0) {
|
|
debug("Zero total distance");
|
|
if (verbose) {
|
|
printf("= %lld * 0 + %lld * 0\n", rails.r1, rails.r2);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
if (rails.r1 == 0 && rails.d % rails.r2 == 0) {
|
|
if (verbose) {
|
|
printf("= %lld * %lld + %lld * 0\n", rails.r1, rails.d / rails.r2,
|
|
rails.r2);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
if (rails.r2 == 0 && rails.d % rails.r1 == 0) {
|
|
if (verbose) {
|
|
printf("= %lld * 0 + %lld * %lld\n", rails.r1, rails.r2,
|
|
rails.d / rails.r1);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
eea_gcd_t eea = extended_euclidian_gcd(rails.r1, rails.r2);
|
|
lli g = eea.g;
|
|
|
|
if (rails.d % g != 0) {
|
|
return 0;
|
|
}
|
|
|
|
ld d_g = (ld)rails.d / (ld)g;
|
|
ld x0 = (ld)eea.x * d_g;
|
|
ld y0 = (ld)eea.y * d_g;
|
|
|
|
|
|
lli a_g = rails.r1 / g;
|
|
lli b_g = rails.r2 / g;
|
|
|
|
lli n_min = (lli)ceil(-x0 / (ld)b_g);
|
|
lli n_max = (lli)floor(y0 / (ld)a_g);
|
|
|
|
if (n_max < n_min) {
|
|
return 0;
|
|
}
|
|
|
|
variants += n_max - n_min + 1;
|
|
|
|
if (verbose) {
|
|
for (lli n = n_min; n <= n_max; n++) {
|
|
lli x = x0 + n * b_g;
|
|
lli y = y0 - n * a_g;
|
|
printf("= %lld * %lld + %lld * %lld\n", rails.r1, x, rails.r2, y);
|
|
}
|
|
}
|
|
|
|
return variants;
|
|
}
|
|
|
|
int main() {
|
|
printf("Delky koleji:\n");
|
|
|
|
lli rail_length_1 = -1, rail_length_2 = -1;
|
|
if (scanf(" %lld %lld", &rail_length_1, &rail_length_2) != 2 ||
|
|
(rail_length_1 <= 0 || rail_length_2 <= 0) ||
|
|
(rail_length_1 == rail_length_2)) {
|
|
return invalid_input();
|
|
}
|
|
|
|
printf("Vzdalenost:\n");
|
|
|
|
lli total_distance = 0;
|
|
char operand;
|
|
|
|
if (scanf(" %c %lld", &operand, &total_distance) != 2 ||
|
|
(operand != '+' && operand != '-')) {
|
|
return invalid_input();
|
|
}
|
|
|
|
if (total_distance < 0) {
|
|
return invalid_input();
|
|
}
|
|
|
|
lli variants = 0;
|
|
bool verbose = operand == '+';
|
|
|
|
if (rail_length_1 > 0 && rail_length_2 > 0) {
|
|
|
|
rails_t rails;
|
|
rails.r1 = rail_length_1;
|
|
rails.r2 = rail_length_2;
|
|
rails.d = total_distance;
|
|
|
|
variants += find_solutions(rails, verbose);
|
|
}
|
|
|
|
if (variants != 0) {
|
|
printf("Celkem variant: %lld\n", variants);
|
|
} else {
|
|
printf("Reseni neexistuje.\n");
|
|
}
|
|
}
|