MARYBMW  BMW
Mary is very very happy. You would be happy too if your parents give you the latest model BMW for your birthday. She wants to try out her new car and that's why she is going to visit her grandma.
There is a graph with N vertices representing N cities and M edges representing bidirectional roads between some pairs of cities. We can assume that Mary lives in city 1 and her grandma lives in city N. Unfortunately, not everything is so good in life and examples are the speed limits. Mary decided to drive with permanent speed. Each of these M roads has a maximum permissible speed V that Mary can't exceed. Well, her whims don't end here. As a lover of the extreme experiences she wants to drive her expensive car as fast as possible.
You are to write a program to find the maximum speed that Mary can reach her grandma's city without having arguments with the policemen (for their own good).
Note: There may be more than one road between two cities.
Input
The first line of the input contains the number of tests – T (T <= 5). On the first line of each test case there are two integers – N (2 <= N <= 50000) and M (1 <= M <= 100000). On the next M lines there are three integers A, B, and V representing a bidirectional road between cities A and B with speed limit V where 1 <= V <= 10^18 (It's a BMW after all).
Output
On a single line print the maximum possible speed Mary can reach. If she can't reach her grandma's house, print 1.
Example
Input:1
4 5
1 2 80
3 1 20
2 3 60
4 3 300
2 4 90
Output:80
hide comments
steady_bunny:
20170613 17:32:30
ITS BMW IT CAN CROSS INT_MAX TOO!!!! 

Vikneshwar E:
20160130 18:40:28
I have tried implementing with both stl list as well as my linked list implementation. But still getting TLE. Excellent problem but time limit is very strict. 

Pulkit Singhal:
20160120 16:15:37
Classical Problem :) 

Advitiya:
20160110 20:18:53
Last edit: 20160118 21:30:22 

cenation:
20151230 10:25:24
Too strict time limit :/ Last edit: 20151230 15:11:36 

secta:
20151228 22:50:56
I increased the time limit from 0.3s to 0.5s :) 
Added by:  Extazy 
Date:  20151228 
Time limit:  0.5s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 GOSU JSMONKEY 