Problem:
Single Source Shortest Path

For a given weighted graph G(V, E) and a source r, find the source shortest path to each vertex from the source (SSSP: Single Source Shortest Path).

Input

An edge-weighted graph G (V, E) and the source r.

|V| |E| r
s0 t0 d0
s1 t1 d1
:
s|E|-1 t|E|-1 d|E|-1

|V| is the number of vertices and |E| is the number of edges in G. The graph vertices are named with the numbers 0, 1,..., |V|-1 respectively. r is the source of the graph.

si and ti represent source and target vertices of i-th edge (directed) and di represents the cost of the i-th edge.

Output

Print the costs of SSSP in the following format.

c0
c1
:
c|V|-1

The output consists of |V| lines. Print the cost of the shortest path from the source r to each vertex 0, 1, ... |V|-1 in order. If there is no path from the source to a vertex, print INF.

Constraints

1 ≤ |V| ≤ 100000

0 ≤ di ≤ 10000

0 ≤ |E| ≤ 500000

There are no parallel edges

There are no self-loops

Sample Input 1

4 5 0
0 1 1
0 2 4
1 2 2
2 3 1
1 3 5

Sample Output 1

0
1
3
4

Sample Input 2

4 6 1
0 1 1
0 2 4
2 0 1
1 2 2
3 1 1
3 2 5

Sample Output 2

3
0
2
INF

Solution in Haskell (judge verdict: Time Limit Exceeded)

import Data.IntMap ((!))
import qualified Data.IntMap as M
import qualified Data.Set as S
import qualified Data.ByteString.Char8 as B
import Control.Applicative
import Data.Maybe
import Data.List
 
type Weight = Int
type Vertex = Int
 
type PriorityQueue = S.Set (Weight, Vertex)
nullq = S.null
empty = S.empty 
push c v = S.insert (c,v)
pop = S.deleteFindMin
 
readEdge = (\[s,t,d] -> (s,[(t,d)])) . map (fst . fromJust . B.readInt) . B.words
 
main = do
 [nv,ne,v0] <- map read . words <$> getLine
 es <- sort . map readEdge . B.lines <$> B.getContents
 let g = foldr (\(k,v) acc -> M.insertWith (++) k v acc) M.empty es
 mapM_ (putStrLn . (\x -> if x == maxBound then "INF" else show x) . sumOfWeight g nv ne v0 es) [0..nv-1]
 
sumOfWeight g nv ne v0 es v = imr!v
 where
  (imr,_) = until (nullq . snd) (dijkstra g) (im0,q0)
  im0 = M.fromDistinctAscList $ zip [0..nv-1] (repeat (maxBound::Int))
  q0 = push 0 v0 S.empty

dijkstra g (im,q) = (im',q'')
 where
  ((d,v),q') = pop q
  im' = M.insertWith min v d im
  q'' = foldr (\(b,c) acc -> push (d+c) b acc) (S.filter ((/=v).snd) q') vns
  vns = filter (\(b,c) -> d+c < im!b) (M.findWithDefault [] v g)