type HeapQueue*[T] = distinct seq[T] proc newHeapQueue*[T](): HeapQueue[T] {.inline.} = HeapQueue[T](newSeq[T]()) proc newHeapQueue*[T](h: var HeapQueue[T]) {.inline.} = h = HeapQueue[T]( newSeq[T]()) proc len*[T](h: HeapQueue[T]): int {.inline.} = seq[T](h).len proc `[]`*[T](h: HeapQueue[T], i: int): T {.inline.} = seq[T](h)[i] proc `[]=`[T](h: var HeapQueue[T], i: int, v: T) {.inline.} = seq[T](h)[i] = v proc add[T](h: var HeapQueue[T], v: T) {.inline.} = seq[T](h).add(v) proc heapCmp[T](x, y: T): bool {.inline.} = return (x < y) # 'heap' is a heap at all indices >= startpos, except possibly for pos. pos # is the index of a leaf with a possibly out-of-order value. Restore the # heap invariant. proc siftdown[T](heap: var HeapQueue[T], startpos, p: int) = var pos = p var newitem = heap[pos] # Follow the path to the root, moving parents down until finding a place # newitem fits. while pos > startpos: let parentpos = (pos - 1) shr 1 let parent = heap[parentpos] if heapCmp(newitem, parent): heap[pos] = parent pos = parentpos else: break heap[pos] = newitem proc siftup[T](heap: var HeapQueue[T], p: int) = let endpos = len(heap) var pos = p let startpos = pos let newitem = heap[pos] # Bubble up the smaller child until hitting a leaf. var childpos = 2*pos + 1 # leftmost child position while childpos < endpos: # Set childpos to index of smaller child. let rightpos = childpos + 1 if rightpos < endpos and not heapCmp(heap[childpos], heap[rightpos]): childpos = rightpos # Move the smaller child up. heap[pos] = heap[childpos] pos = childpos childpos = 2*pos + 1 # The leaf at pos is empty now. Put newitem there, and bubble it up # to its final resting place (by sifting its parents down). heap[pos] = newitem siftdown(heap, startpos, pos) proc push*[T](heap: var HeapQueue[T], item: T) = ## Push item onto heap, maintaining the heap invariant. (seq[T](heap)).add(item) siftdown(heap, 0, len(heap)-1) proc pop*[T](heap: var HeapQueue[T]): T = ## Pop the smallest item off the heap, maintaining the heap invariant. let lastelt = seq[T](heap).pop() if heap.len > 0: result = heap[0] heap[0] = lastelt siftup(heap, 0) else: result = lastelt # https://github.com/nim-lang/Nim/blob/master/lib/pure/collections/heapqueue.nim # ---------------------------------------------------------------------------------------------- # # ---------------------------------------------------------------------------------------------- # import strutils, sequtils, math proc `<`[T](a, b: T): bool {.inline.} = return a.dist < b.dist proc main() = let nm = stdin.readLine.strip.split.map(parseInt) (n, m) = (nm[0], nm[1]) abci = (0.. 0: let cur = q.pop for e in g[cur.node]: if cur.dist + e.cost < dist[e.to][cur.used]: dist[e.to][cur.used] = cur.dist + e.cost q.add(T(node: e.to, dist: dist[e.to][cur.used], used: cur.used)) if (cur.used == 0) and (cur.dist < dist[e.to][1]): dist[e.to][1] = cur.dist q.add(T(node: e.to, dist: dist[e.to][1], used: 1)) for i in 0..