Kruskal's Algorithm - Java vs. Go vs. JavaScript vs. Swift vs. Lisp

As part of my studies I implemented Kruskal's Algorithm in Java. To see how it would compare, I decided to implement the Algorithm in Go, JavaScript, Swift and plain C as well. On my system the Go implementation turned out to be the fastest. A classmate implemented the Algorithm also in Common Lisp

The program accepts data in the stdin and returns its result to stdout. An example for input data is shown in test.in with the corresponding correct output in test.out.

The first integer is the number of problems. Each problem consists first of two integers 1 ≤ n,m indicating the number of vertices and edges respectively. Then follow m pairs of three integers representing an edge. The first two integers denote the vertices on each end of the edge, while the third integer denotes the edge's weight.

Execution time

These are the execution times on my system for the test data included in test.in.

C:

real    0m0.043s
user    0m0.037s
sys     0m0.004s

Go:

real    0m0.047s
user    0m0.039s
sys     0m0.006s

JavaScript (Node.js):

real    0m0.192s
user    0m0.170s
sys     0m0.023s

Objective-C:

real    0m0.240s
user    0m0.227s
sys     0m0.007s

Swift:

real    0m0.533s
user    0m0.524s
sys     0m0.007s

Java:

real    0m0.279s
user    0m0.622s
sys     0m0.062s

PHP:

real    0m6.593s
user    0m6.534s
sys     0m0.030s

Lisp (Common Lisp):

real    0m0.156s
user    0m0.135s
sys     0m0.016s

###Haskell:

real	0m1.634s
user    0m1.600s
sys     0m0.021s