Update run_all.py

Fix printing total run time.

run_all.py

@@ -5,11 +5,11 @@ from os.path import isdir, isfile
 from subprocess import Popen, PIPE, CalledProcessError
 from time import time
 
-
+total_run_time = 0
 for dir in [x for x in sorted(listdir('.')) if isdir(x)]:
     file = dir + '/' + dir + '.py'
     input = dir + '/input.txt'
-    total_run_time = 0
+
     if isfile(file) and isfile(input):
         print('--------------------------------')
         print(dir, ':', sep='')