# Project Euler 170
# Largest 0-9 pandigital formed by concatenating products of a common factor.
import euler.nt { gcd }
function is_pandigital_mask(x0: i64) -> bool {
let mut used: i32 = 0
let mut x: i64 = x0
let mut digits: i32 = 0
while x > 0 {
let d: i32 = (x % 10) as i32
let bit: i32 = 1 << d
if (used & bit) != 0 { return false }
used = used | bit
digits = digits + 1
x = x / 10
}
return digits == 10 && used == 1023
}
function is_pandigital_var(x0: i64) -> bool {
let mut used: i32 = 0
let mut x: i64 = x0
if x == 0 { return false }
while x > 0 {
let d: i32 = (x % 10) as i32
let bit: i32 = 1 << d
if (used & bit) != 0 { return false }
used = used | bit
x = x / 10
}
return true
}
function digit_len(x0: i64) -> i32 {
if x0 == 0 { return 1 }
let mut n: i32 = 0
let mut x: i64 = x0
while x > 0 {
n = n + 1
x = x / 10
}
return n
}
function concat3(a: i64, b: i64, c: i64) -> i64 {
let mut powb: i64 = 1
let mut t: i64 = b
if t == 0 { powb = 10 } else {
while t > 0 { powb = powb * 10; t = t / 10 }
}
let mut powc: i64 = 1
t = c
if t == 0 { powc = 10 } else {
while t > 0 { powc = powc * 10; t = t / 10 }
}
return (a * powb + b) * powc + c
}
function pow10(n: i32) -> i64 {
let mut r: i64 = 1
for i in 0..n {
r = r * 10
}
return r
}
function prev_perm(d: ptr<i8>) -> bool {
let mut i: i32 = 8
while i >= 0 && d[i] <= d[i + 1] {
i = i - 1
}
if i < 0 { return false }
let mut j: i32 = 9
while d[j] >= d[i] {
j = j - 1
}
let tmp: i8 = d[i]
d[i] = d[j]
d[j] = tmp
let mut a: i32 = i + 1
let mut b: i32 = 9
while a < b {
let t2: i8 = d[a]
d[a] = d[b]
d[b] = t2
a = a + 1
b = b - 1
}
return true
}
function digits_to_num(d: ptr<i8>) -> i64 {
let mut n: i64 = 0
for i in 0..10 {
n = n * 10 + (d[i] as i64)
}
return n
}
function main() -> i32 {
let mut d: array<i8, 10> = [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
while true {
let current: i64 = digits_to_num(d)
for split in 1..10 {
if d[0] != 0 && d[split] != 0 {
let left: i64 = 0
for i in 0..split {
left = left * 10 + (d[i] as i64)
}
let right: i64 = 0
for i in split..10 {
right = right * 10 + (d[i] as i64)
}
let shared: i64 = gcd(left, right)
for factor in 3..(shared + 1) step 3 {
if left % factor == 0 && right % factor == 0 {
let one: i64 = left / factor
let two: i64 = right / factor
let seq: i64 = concat3(factor, one, two)
if digit_len(seq) == 10 && is_pandigital_mask(seq) {
printf("%lld\n", current)
return 0
}
}
}
}
}
if prev_perm(d) == false { break }
}
printf("0\n")
return 1
}
Generated C
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Flow runtime helpers */
typedef struct flow_temp_node { struct flow_temp_node* next; } flow_temp_node;
static flow_temp_node* flow_temp_head = NULL;
static int flow_temp_atexit_set = 0;
__attribute__((unused)) static void flow_temp_free_all(void) {
while (flow_temp_head) {
flow_temp_node* n = flow_temp_head;
flow_temp_head = n->next;
free(n);
}
}
__attribute__((unused)) static void* flow_temp_alloc(size_t nbytes) {
flow_temp_node* node = (flow_temp_node*)malloc(sizeof(flow_temp_node) + nbytes);
if (!node) return NULL;
node->next = flow_temp_head;
flow_temp_head = node;
if (!flow_temp_atexit_set) {
flow_temp_atexit_set = 1;
atexit(flow_temp_free_all);
}
return (void*)(node + 1);
}
#ifndef FLOW_DIAG
#define FLOW_DIAG(msg) fprintf(stderr, "%s", (msg))
#endif
#ifndef FLOW_LOG
#define FLOW_LOG(fmt, ...) printf(fmt, __VA_ARGS__)
#endif
#ifndef FLOW_LOG_EMPTY
#define FLOW_LOG_EMPTY(fmt) printf(fmt)
#endif
static char* flow_strcat(const char* a, const char* b) {
size_t la = strlen(a ? a : ""), lb = strlen(b ? b : "");
char* r = (char*)flow_temp_alloc(la + lb + 1);
if (!r) return NULL;
if (la) memcpy(r, a, la);
if (lb) memcpy(r + la, b, lb);
r[la + lb] = '\0';
return r;
}
#define __flow_in_arr(arr, val) __extension__ ({ \
int _found = 0; \
size_t _n = sizeof(arr)/sizeof((arr)[0]); \
for (size_t _i = 0; _i < _n; _i++) { \
if ((arr)[_i] == (val)) { _found = 1; break; } \
} _found; })
/* Unified fault handler (MISRA #279) — override with -DFLOW_FAULT_HANDLER=fn */
#ifndef FLOW_FAULT_HANDLER
__attribute__((unused)) static inline void flow_fault_handler(const char* msg) {
fprintf(stderr, "flow: %s\n", msg ? msg : "fault");
abort();
#if defined(__GNUC__) || defined(__clang__)
__builtin_unreachable();
#endif
}
#else
#define flow_fault_handler FLOW_FAULT_HANDLER
#endif
#define flow_div_by_zero_handler() flow_fault_handler("division by zero")
#define flow_shift_ub_handler() flow_fault_handler("invalid shift (amount out of range or left-shift of negative)")
#ifndef FLOW_CHECKED_DIV
#define FLOW_CHECKED_DIV(L, R) (((R) != 0) ? ((L) / (R)) : (flow_div_by_zero_handler(), (L) * 0))
#endif
#ifndef FLOW_CHECKED_MOD
#define FLOW_CHECKED_MOD(L, R) (((R) != 0) ? ((L) % (R)) : (flow_div_by_zero_handler(), (L) * 0))
#endif
#ifndef FLOW_CHECKED_SHL
#define FLOW_CHECKED_SHL(L, R) ((((R) >= 0) && ((unsigned long long)(R) < (sizeof(L) * 8ull)) && ((L) >= 0)) ? ((L) << (R)) : (flow_shift_ub_handler(), (L) * 0))
#endif
#ifndef FLOW_CHECKED_SHR
#define FLOW_CHECKED_SHR(L, R) ((((R) >= 0) && ((unsigned long long)(R) < (sizeof(L) * 8ull))) ? ((L) >> (R)) : (flow_shift_ub_handler(), (L) * 0))
#endif
#include <math.h>
void* _ui_state = NULL;
static inline float i32_to_f32(int32_t v) { return (float)v; }
/* Host stub for @gpu kernels (device codegen replaces this). */
static inline int32_t gpu_thread_id(void) { return 0; }
int64_t gcd_i64_i64(int64_t a0, int64_t b0);
int64_t lcm_i64_i64(int64_t a, int64_t b);
int64_t isqrt_i64(int64_t n);
int64_t mulmod_i64_i64_i64(int64_t a0, int64_t b0, int64_t mod);
int64_t mod_pow_i64_i64_i64(int64_t base, int64_t exp, int64_t mod);
bool is_prime_i64(int64_t n);
bool is_pandigital_mask_i64(int64_t x0);
bool is_pandigital_var_i64(int64_t x0);
int32_t digit_len_i64(int64_t x0);
int64_t concat3_i64_i64_i64(int64_t a, int64_t b, int64_t c);
int64_t pow10_i32(int32_t n);
bool prev_perm_ptr_i8(int8_t* d);
int64_t digits_to_num_ptr_i8(int8_t* d);
int32_t main(void);
int64_t gcd_i64_i64(int64_t a0, int64_t b0) {
int64_t a = a0;
int64_t b = b0;
while (b != 0) {
int64_t t = FLOW_CHECKED_MOD((a), (b));
a = b;
b = t;
}
return a;
}
int64_t lcm_i64_i64(int64_t a, int64_t b) {
if ((a == 0 || b == 0)) {
return 0;
}
return (FLOW_CHECKED_DIV((a), (gcd_i64_i64(a, b))) * b);
}
int64_t isqrt_i64(int64_t n) {
if (n < 2) {
return n;
}
int64_t x = n;
int64_t y = FLOW_CHECKED_DIV(((x + 1)), (2));
while (y < x) {
x = y;
y = FLOW_CHECKED_DIV(((x + FLOW_CHECKED_DIV((n), (x)))), (2));
}
return x;
}
int64_t mulmod_i64_i64_i64(int64_t a0, int64_t b0, int64_t mod) {
int64_t a = FLOW_CHECKED_MOD((a0), (mod));
int64_t b = FLOW_CHECKED_MOD((b0), (mod));
int64_t result = 0;
while (b > 0) {
if (FLOW_CHECKED_MOD((b), (2)) == 1) {
result = FLOW_CHECKED_MOD(((result + a)), (mod));
}
a = FLOW_CHECKED_MOD(((a * 2)), (mod));
b = FLOW_CHECKED_DIV((b), (2));
}
return result;
}
int64_t mod_pow_i64_i64_i64(int64_t base, int64_t exp, int64_t mod) {
if (mod == 1) {
return 0;
}
int64_t result = 1;
int64_t b = FLOW_CHECKED_MOD((base), (mod));
int64_t e = exp;
while (e > 0) {
if (FLOW_CHECKED_MOD((e), (2)) == 1) {
result = mulmod_i64_i64_i64(result, b, mod);
}
b = mulmod_i64_i64_i64(b, b, mod);
e = FLOW_CHECKED_DIV((e), (2));
}
return result;
}
bool is_prime_i64(int64_t n) {
if (n < 2) {
return 0;
}
if (n < 4) {
return 1;
}
if ((FLOW_CHECKED_MOD((n), (2)) == 0 || FLOW_CHECKED_MOD((n), (3)) == 0)) {
return 0;
}
int64_t i = 5;
while ((i * i) <= n) {
if ((FLOW_CHECKED_MOD((n), (i)) == 0 || FLOW_CHECKED_MOD((n), ((i + 2))) == 0)) {
return 0;
}
i = (i + 6);
}
return 1;
}
bool is_pandigital_mask_i64(int64_t x0) {
int32_t used = 0;
int64_t x = x0;
int32_t digits = 0;
while (x > 0) {
int32_t d = ((int32_t)(FLOW_CHECKED_MOD((x), (10))));
int32_t bit = FLOW_CHECKED_SHL((1), (d));
if ((used & bit) != 0) {
return 0;
}
used = (used | bit);
digits = (digits + 1);
x = FLOW_CHECKED_DIV((x), (10));
}
return (digits == 10 && used == 1023);
}
bool is_pandigital_var_i64(int64_t x0) {
int32_t used = 0;
int64_t x = x0;
if (x == 0) {
return 0;
}
while (x > 0) {
int32_t d = ((int32_t)(FLOW_CHECKED_MOD((x), (10))));
int32_t bit = FLOW_CHECKED_SHL((1), (d));
if ((used & bit) != 0) {
return 0;
}
used = (used | bit);
x = FLOW_CHECKED_DIV((x), (10));
}
return 1;
}
int32_t digit_len_i64(int64_t x0) {
if (x0 == 0) {
return 1;
}
int32_t n = 0;
int64_t x = x0;
while (x > 0) {
n = (n + 1);
x = FLOW_CHECKED_DIV((x), (10));
}
return n;
}
int64_t concat3_i64_i64_i64(int64_t a, int64_t b, int64_t c) {
int64_t powb = 1;
int64_t t = b;
if (t == 0) {
powb = 10;
} else {
while (t > 0) {
powb = (powb * 10);
t = FLOW_CHECKED_DIV((t), (10));
}
}
int64_t powc = 1;
t = c;
if (t == 0) {
powc = 10;
} else {
while (t > 0) {
powc = (powc * 10);
t = FLOW_CHECKED_DIV((t), (10));
}
}
return ((((a * powb) + b) * powc) + c);
}
int64_t pow10_i32(int32_t n) {
int64_t r = 1;
int32_t __flow_step_1 = 1;
for (int32_t i = 0; (0 <= n) ? i < n : i > n; i += (0 <= n) ? 1 : -1) {
r = (r * 10);
}
return r;
}
bool prev_perm_ptr_i8(int8_t* d) {
int32_t i = 8;
while ((i >= 0 && d[i] <= d[(i + 1)])) {
i = (i - 1);
}
if (i < 0) {
return 0;
}
int32_t j = 9;
while (d[j] >= d[i]) {
j = (j - 1);
}
int8_t tmp = d[i];
d[i] = d[j];
d[j] = tmp;
int32_t a = (i + 1);
int32_t b = 9;
while (a < b) {
int8_t t2 = d[a];
d[a] = d[b];
d[b] = t2;
a = (a + 1);
b = (b - 1);
}
return 1;
}
int64_t digits_to_num_ptr_i8(int8_t* d) {
int64_t n = 0;
int32_t __flow_step_2 = 1;
for (int32_t i = 0; (0 <= 10) ? i < 10 : i > 10; i += (0 <= 10) ? 1 : -1) {
n = ((n * 10) + ((int64_t)(d[i])));
}
return n;
}
int32_t main(void) {
int8_t d[10] = { 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 };
while (1) {
int64_t current = digits_to_num_ptr_i8(d);
int32_t __flow_step_3 = 1;
for (int32_t split = 1; (1 <= 10) ? split < 10 : split > 10; split += (1 <= 10) ? 1 : -1) {
if (((((unsigned)(0) < 10) ? d[0] : (fprintf(stderr, "array index %d out of bounds (size %d)\n", (int)(0), 10), flow_fault_handler("array index out of bounds"), d[0])) != 0 && (((unsigned)(split) < 10) ? d[split] : (fprintf(stderr, "array index %d out of bounds (size %d)\n", (int)(split), 10), flow_fault_handler("array index out of bounds"), d[0])) != 0)) {
int64_t left = 0;
int32_t __flow_step_4 = 1;
for (int32_t i = 0; (0 <= split) ? i < split : i > split; i += (0 <= split) ? 1 : -1) {
left = ((left * 10) + ((int64_t)((((unsigned)(i) < 10) ? d[i] : (fprintf(stderr, "array index %d out of bounds (size %d)\n", (int)(i), 10), flow_fault_handler("array index out of bounds"), d[0])))));
}
int64_t right = 0;
int32_t __flow_step_5 = 1;
for (int32_t i = split; (split <= 10) ? i < 10 : i > 10; i += (split <= 10) ? 1 : -1) {
right = ((right * 10) + ((int64_t)((((unsigned)(i) < 10) ? d[i] : (fprintf(stderr, "array index %d out of bounds (size %d)\n", (int)(i), 10), flow_fault_handler("array index out of bounds"), d[0])))));
}
int64_t shared = gcd_i64_i64(left, right);
int32_t __flow_step_6 = 3;
for (int32_t factor = 3; (__flow_step_6 > 0) ? factor < (shared + 1) : factor > (shared + 1); factor += __flow_step_6) {
if ((FLOW_CHECKED_MOD((left), (factor)) == 0 && FLOW_CHECKED_MOD((right), (factor)) == 0)) {
int64_t one = FLOW_CHECKED_DIV((left), (factor));
int64_t two = FLOW_CHECKED_DIV((right), (factor));
int64_t seq = concat3_i64_i64_i64(factor, one, two);
if ((digit_len_i64(seq) == 10 && is_pandigital_mask_i64(seq))) {
printf("%lld\n", current);
return 0;
}
}
}
}
}
if (prev_perm_ptr_i8(d) == 0) {
break;
}
}
printf("0\n");
return 1;
}