# Project Euler 083
# Minimal path sum with four-way moves (Dijkstra).
extern {
function fopen(path: string, mode: string) -> ptr<void>
function fgetc(f: ptr<void>) -> i32
function fclose(f: ptr<void>) -> i32
function calloc(n: i64, size: i64) -> ptr<void>
function free(p: ptr<void>) -> void
}
function read_int(f: ptr<void>) -> i32 {
let mut c: i32 = fgetc(f)
while c >= 0 && (c < 48 || c > 57) {
c = fgetc(f)
}
if c < 0 { return -1 }
let mut v: i32 = 0
while c >= 48 && c <= 57 {
v = v * 10 + (c - 48)
c = fgetc(f)
}
return v
}
function main() -> i32 {
let n: i32 = 80
let N: i32 = n * n
let a: ptr<i64> = calloc(N as i64, 8)
let dist: ptr<i64> = calloc(N as i64, 8)
let done: ptr<i8> = calloc(N as i64, 1)
if a == null || dist == null || done == null { return 1 }
let f: ptr<void> = fopen("data/p083.txt", "r")
if f == null {
printf("failed to read data/p083.txt\n")
return 1
}
let mut i: i32 = 0
while i < N {
a[i] = read_int(f) as i64
dist[i] = 1000000000000
i = i + 1
}
fclose(f)
dist[0] = a[0]
let mut iter: i32 = 0
while iter < N {
let mut u: i32 = -1
let mut best: i64 = 1000000000000
let mut v: i32 = 0
while v < N {
if done[v] == 0 && dist[v] < best {
best = dist[v]
u = v
}
v = v + 1
}
if u < 0 { break }
done[u] = 1
let r: i32 = u / n
let c: i32 = u % n
# neighbors
let mut k: i32 = 0
while k < 4 {
let mut nr: i32 = r
let mut nc: i32 = c
match k {
0 => { nr = r - 1 }
1 => { nr = r + 1 }
2 => { nc = c - 1 }
_ => { nc = c + 1 }
}
if nr >= 0 && nr < n && nc >= 0 && nc < n {
let w: i32 = nr * n + nc
let nd: i64 = dist[u] + a[w]
if nd < dist[w] {
dist[w] = nd
}
}
k = k + 1
}
iter = iter + 1
}
printf("%lld\n", dist[N - 1])
free(a)
free(dist)
free(done)
return 0
}
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; }
int32_t read_int_ptr_void(void* f);
int32_t main(void);
int32_t read_int_ptr_void(void* f) {
int32_t c = fgetc(f);
while ((c >= 0 && (c < 48 || c > 57))) {
c = fgetc(f);
}
if (c < 0) {
return (-1);
}
int32_t v = 0;
while ((c >= 48 && c <= 57)) {
v = ((v * 10) + (c - 48));
c = fgetc(f);
}
return v;
}
int32_t main(void) {
int32_t n = 80;
int32_t N = (n * n);
int64_t* a = (int64_t*)(calloc(((int64_t)(N)), 8));
int64_t* dist = (int64_t*)(calloc(((int64_t)(N)), 8));
int8_t* done = (int8_t*)(calloc(((int64_t)(N)), 1));
if (((a == NULL || dist == NULL) || done == NULL)) {
return 1;
}
void* f = (void*)(fopen("data/p083.txt", "r"));
if (f == NULL) {
printf("failed to read data/p083.txt\n");
return 1;
}
int32_t i = 0;
while (i < N) {
a[i] = ((int64_t)(read_int_ptr_void(f)));
dist[i] = 1000000000000;
i = (i + 1);
}
fclose(f);
dist[0] = a[0];
int32_t iter = 0;
while (iter < N) {
int32_t u = (-1);
int64_t best = 1000000000000;
int32_t v = 0;
while (v < N) {
if ((done[v] == 0 && dist[v] < best)) {
best = dist[v];
u = v;
}
v = (v + 1);
}
if (u < 0) {
break;
}
done[u] = 1;
int32_t r = FLOW_CHECKED_DIV((u), (n));
int32_t c = FLOW_CHECKED_MOD((u), (n));
int32_t k = 0;
while (k < 4) {
int32_t nr = r;
int32_t nc = c;
{ // match block
if ((k) == 0) {
nr = (r - 1);
} else if ((k) == 1) {
nr = (r + 1);
} else if ((k) == 2) {
nc = (c - 1);
} else { // exhaustive
nc = (c + 1);
}
} // end match
if ((((nr >= 0 && nr < n) && nc >= 0) && nc < n)) {
int32_t w = ((nr * n) + nc);
int64_t nd = (dist[u] + a[w]);
if (nd < dist[w]) {
dist[w] = nd;
}
}
k = (k + 1);
}
iter = (iter + 1);
}
printf("%lld\n", dist[(N - 1)]);
free(a);
free(dist);
free(done);
return 0;
}