結果

問題 No.160 最短経路のうち辞書順最小
コンテスト
ユーザー chaemon
提出日時 2019-07-23 00:25:24
言語 Nim
(2.2.0)
結果
AC  
実行時間 13 ms / 5,000 ms
コード長 4,192 bytes
コンパイル時間 3,418 ms
コンパイル使用メモリ 72,332 KB
実行使用メモリ 7,552 KB
最終ジャッジ日時 2024-07-02 05:55:16
合計ジャッジ時間 4,740 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 4
other AC * 26
権限があれば一括ダウンロードができます
コンパイルメッセージ
/home/judge/data/code/Main.nim(2, 37) Warning: imported and not used: 'macros' [UnusedImport]
/home/judge/data/code/Main.nim(2, 45) Warning: imported and not used: 'math' [UnusedImport]
/home/judge/data/code/Main.nim(2, 29) Warning: imported and not used: 'tables' [UnusedImport]

ソースコード

diff # 

#{{{ header
import algorithm, sequtils, tables, macros, math, sets, strutils
when defined(MYDEBUG):
  import header

proc scanf(formatstr: cstring){.header: "<stdio.h>", varargs.}
proc getchar(): char {.header: "<stdio.h>", varargs.}
proc nextInt(): int = scanf("%lld",addr result)
proc nextFloat(): float = scanf("%lf",addr result)
proc nextString(): string =
  var get = false
  result = ""
  while true:
    var c = getchar()
    if int(c) > int(' '):
      get = true
      result.add(c)
    else:
      if get: break
      get = false
template `max=`*(x,y:typed):void = x = max(x,y)
template `min=`*(x,y:typed):void = x = min(x,y)
template infty(T): untyped = ((T(1) shl T(sizeof(T)*8-2)) - 1)
#}}}

#{{{ Graph
type Edge = object
  src,dst:int
  weight:int
  rev:int

proc newEdge(src,dst:int,weight:int = 1,rev:int = -1):Edge =
  var e:Edge
  e.src = src
  e.dst = dst
  e.weight = weight
  e.rev = rev
  return e

proc `<`(l,r:Edge):bool = 
  return l.weight < r.weight

type Graph = seq[seq[Edge]]

proc newGraph(n:int):Graph=
  var g:Graph
  g = newSeqWith(n,newSeq[Edge]())
  return g

proc addBiEdge(g:var Graph,src,dst:int,weight:int=1):void =
  g[src].add(newEdge(src,dst,weight,g[dst].len))
  g[dst].add(newEdge(dst,src,weight,g[src].len-1))

proc addEdge(g:var Graph,src,dst:int,weight:int=1):void =
  g[src].add(newEdge(src,dst,weight,-1))
#}}}

proc cmp2(l,r:Edge):int = 
  if l.dst < r.dst : -1 else: 1

import heapqueue

proc shortest_path(g:Graph, s:int): (seq[int],seq[int]) = 
  var
    n = g.len
    dist = newSeqWith(n,int.infty)
    prev = newSeqWith(n,-1)
    Q = initHeapQueue[Edge]()
  dist[s] = 0
  Q.push(newEdge(-2,s,0))
  while Q.len > 0:
    var e = Q.pop()
    if prev[e.dst] != -1: continue
    prev[e.dst] = e.src;
    for f in g[e.dst]:
      var w = e.weight + f.weight;
      if dist[f.dst] > w:
        dist[f.dst] = w;
        Q.push(newEdge(f.src, f.dst, w));
    discard
  return (dist,prev)
#//{{{ shortest_path(graph g, int s) : Dijkstra
#template<class Weight>
#	const graph<Weight> &g;
#	const int &s;
#	vector<Weight> dist;
#	vector<int> prev;
#//	dijkstra_t(const graph<Weight> &g,int s):g(g),s(s),dist(g.size(),g.inf),prev(g.size(),-1){}
#	dijkstra_t(const graph<Weight> &g,const int &s):g(g),s(s),dist(g.size(),g.inf),prev(g.size(),-1){
#		/*
#		assert(dist.size()==g.size());
#		REP(i,dist.size())assert(dist[i]>=0 and dist[i]+dist[i]>=0);
#		*/
#	}
#	vector<int> path(int t) {
#		vector<int> path;
#		for (int u = t; u >= 0; u = prev[u])path.push_back(u);
#		reverse(ALL(path));
#		return path;
#	}
#	void dijkstra(){
#		dist[s] = 0;
#		priority_queue<edge<Weight> > Q; // "e < f" <=> "e.weight > f.weight"
#		for (Q.push(edge<Weight>(-2, s, 0)); !Q.empty(); ) {
#			edge<Weight> e = Q.top(); Q.pop();
#			if (prev[e.dst] != -1) continue;
#			prev[e.dst] = e.src;
#			for(auto f:g[e.dst]) {
#//				assert(e.weight<=g.inf);
#//				assert(0<=f.weight and f.weight<=g.inf);
#				Weight w = e.weight + f.weight;
#				if (dist[f.dst] > w) {
#					dist[f.dst] = w;
#					Q.push(edge<Weight>(f.src, f.dst, w));
#				}
#			}
#		}
#	}
#	/*
#	void count_dp(){
#		vector<pair<Weight,int> > d;
#		REP(u,g.size())d.push_back({dist[u],u});
#		sort(ALL(d));
#		dp.assign(g.size(),mod_int());
#		dp[s] = 1;
#		REP(i,d.size()){
#			int u = d[i].second;
#			for(auto &&e:g[u]){
#				if(dist[e.dst]+e.weight==dist[u]){
#					dp[u]+=dp[e.dst];
#				}
#			}
#		}
#	}
#	*/
#};
#template<class Weight>
#dijkstra_t<Weight> shortest_path(const graph<Weight> &g, int s) {
#	dijkstra_t<Weight> ret(g,s);
#	ret.dijkstra();
#//	ret.count_dp();
#	return ret;
#}
#//}}}

proc main():void =
  var
    N = nextInt()
    M = nextInt()
    S = nextInt()
    G = nextInt()
    a = newSeq[int](M)
    b = newSeq[int](M)
    c = newSeq[int](M)
    g = newGraph(N)
  for i in 0..M-1:
    a[i] = nextInt();b[i] = nextInt();c[i] = nextInt()
    g.addBiEdge(a[i],b[i],c[i])
  for u in 0..N-1:
    g[u].sort(cmp2)
  var (dist,_) = shortest_path(g,G)
  var
    cur = S
    ans = newSeq[int]()
  while cur != G:
    ans.add(cur)
    for e in g[cur]:
      if dist[cur] == dist[e.dst] + e.weight:
        cur = e.dst
        break
  ans.add(cur)
  echo ans.join(" ")
  discard

main()
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