#include #include #include #include typedef struct binary_heap { void *array; size_t heap_size; size_t max_size; size_t val_size; int (*cmp) (const void *, const void *); } heap; heap* new_binary_heap (const size_t val_size, int (*cmp_func) (const void *, const void *)) { heap *h = (heap *) calloc (1, sizeof (heap)); h->array = malloc (val_size * (1 + 1)); h->heap_size = 0; h->max_size = 1; h->val_size = val_size; h->cmp = cmp_func; return h; } int is_empty (const heap *h) { return h->heap_size == 0; } static inline void heap_func_swap (void * restrict a, void * restrict b, size_t val_size) { if ((val_size & 7) == 0) { uint64_t *p = (uint64_t *) a; uint64_t *q = (uint64_t *) b; val_size /= sizeof (uint64_t); while (val_size--) { const uint64_t tmp = *p; *p++ = *q; *q++ = tmp; } } else { uint8_t *p = (uint8_t *) a; uint8_t *q = (uint8_t *) b; while (val_size--) { const uint8_t tmp = *p; *p++ = *q; *q++ = tmp; } } } static inline void heap_func_copy (void * restrict dst, const void * restrict src, size_t val_size) { if ((val_size & 7) == 0) { const uint64_t *p = (const uint64_t *) src; uint64_t *q = (uint64_t *) dst; val_size /= sizeof (uint64_t); while (val_size--) { *q++ = *p++; } } else { const uint8_t *p = (const uint8_t *) src; uint8_t *q = (uint8_t *) dst; while (val_size--) { *q++ = *p++; } } } void push (heap * const h, const void *val) { if (h->heap_size == h->max_size) { h->max_size = 2 * h->max_size + 1; h->array = realloc (h->array, h->val_size * (h->max_size + 1)); } h->heap_size++; uint8_t * const array = (uint8_t *) h->array; size_t k = h->heap_size; const size_t val_size = h->val_size; int (* const cmp) (const void *, const void *) = h->cmp; heap_func_copy(array + k * val_size, val, val_size); while (k > 1) { size_t parent = k / 2; if (cmp (array + parent * val_size, array + k * val_size) <= 0) { return; } heap_func_swap (array + parent * val_size, array + k * val_size, val_size); k = parent; } } void pop (heap * const h, void *res) { uint8_t * const array = (uint8_t *) h->array; const size_t val_size = h->val_size; if (res != NULL) { heap_func_copy (res, array + val_size, val_size); } heap_func_copy (array + val_size, array + val_size * h->heap_size, val_size); h->heap_size--; int (* const cmp) (const void *, const void *) = h->cmp; const size_t n = h->heap_size; size_t k = 1; while (2 * k + 1 <= n) { const int c = cmp (array + val_size * 2 * k, array + val_size * (2 * k + 1)); const size_t next = 2 * k + (c <= 0 ? 0 : 1); if (cmp (array + val_size * k, array + val_size * next) <= 0) return; heap_func_swap (array + val_size * k, array + val_size * next, val_size); k = next; } if (2 * k <= n && cmp (array + val_size * k, array + val_size * 2 * k) > 0) { heap_func_swap (array + val_size * k, array + val_size * 2 * k, val_size); } } typedef int32_t i32; typedef int64_t i64; typedef int32_t edge_weight; typedef struct directed_edge { int32_t vertex; int32_t next; edge_weight cost; } graph_edge; typedef struct directedGraph { graph_edge *edge; int32_t *start; int32_t pointer; int32_t vertex_num; int32_t edge_max_size; } graph; graph* new_graph (const int vertex_num) { graph *g = (graph *) calloc (1, sizeof (graph)); g->edge = (graph_edge *) calloc (1, sizeof (graph_edge)); g->start = (int32_t *) calloc (vertex_num, sizeof (int32_t)); g->pointer = 0; g->vertex_num = vertex_num; g->edge_max_size = 1; for (int32_t i = 0; i < vertex_num; ++i) { g->start[i] = -1; } return g; } void add_edge (graph *g, int32_t from, int32_t to, edge_weight cost) { if (g->pointer == g->edge_max_size) { g->edge_max_size *= 2; g->edge = (graph_edge *) realloc (g->edge, sizeof (graph_edge) * g->edge_max_size); } g->edge[g->pointer] = (graph_edge) {to, g->start[from], cost}; g->start[from] = g->pointer++; } #define MAX(a,b) ((a)>(b)?(a):(b)) #define MIN(a,b) ((a)<(b)?(a):(b)) #define ABS(a) ((a)>(0)?(a):-(a)) #define ALLOC(size,type) ((type*)calloc((size),sizeof(type))) #define SORT(a,num,cmp) qsort((a),(num),sizeof(*(a)),cmp) typedef struct node { i32 v; i64 d; } node; int cmp_node (const void *a, const void *b) { i64 d = ((node *)a)->d - ((node *)b)->d; return d == 0 ? 0 : d < 0 ? -1 : 1; } i64* dijkstra (graph *g, i32 src) { i32 n = g->vertex_num; i64 *dp = ALLOC (n, i64); const i64 inf = (i64) 2000 * 1000000000; for (i32 i = 0; i < n; ++i) { dp[i] = inf; } dp[src] = 0; static heap *h = NULL; if (h == NULL) { h = new_binary_heap (sizeof (node), cmp_node); } push (h, &(node){src, 0}); while (!is_empty (h)) { node t; pop (h, &t); if (t.d > dp[t.v]) continue; for (i32 p = g->start[t.v]; p != -1; p = g->edge[p].next) { i32 u = g->edge[p].vertex; i64 d = t.d + g->edge[p].cost; if (d >= dp[u]) continue; dp[u] = d; push (h, &(node){u, d}); } } return dp; } void run (void) { i32 n, m, p, q, t; scanf ("%" SCNi32 "%" SCNi32 "%" SCNi32 "%" SCNi32 "%" SCNi32, &n, &m, &p, &q, &t); p--; q--; graph *g = new_graph (n); while (m--) { i32 a, b, c; scanf ("%" SCNi32 "%" SCNi32 "%" SCNi32, &a, &b, &c); a--; b--; add_edge (g, a, b, c); add_edge (g, b, a, c); } i64 *dp_0 = dijkstra (g, 0); i64 *dp_p = dijkstra (g, p); i64 *dp_q = dijkstra (g, q); if (2 * dp_0[p] > t || 2 * dp_0[q] > t) { puts ("-1"); return; } if (dp_0[p] + dp_p[q] + dp_q[0] <= t) { printf ("%" PRIi32 "\n", t); return; } i64 max = 0; for (i32 i = 0; i < n; ++i) { for (i32 j = 0; j < n; ++j) { i64 x = dp_0[i] + dp_p[i] + dp_p[j] + dp_0[j]; i64 y = dp_0[i] + dp_q[i] + dp_q[j] + dp_0[j]; if (x <= t && y <= t) { max = MAX (max, dp_0[i] + dp_0[j] + t - MAX(x, y)); } } } printf ("%" PRIi64 "\n", max); } int main (void) { run(); return 0; }