Single Source Shortest Path
Given a directed graph G by edge list
Find the shortest path from s to t
The first line is an integer T, the number of testcases.
For each testcase:
The first line has 4 integers n,m,s,t : the number of vertices, edges, start, destination
There are m lines below, each represent a directed edge
Each edge has three positive integers v, u, c: an edge from v to u whose cost is c
n<=100000
m<=300000
vertices are indexed from 1 to n, c<=1000
For each testcase print the cost of the shortest path from s to t
If there is no path from s to t, print "OAO"