We have list of triangles, or "triangles", and we need to find which ones are possible. In euclidean geometry, that is, not something from Cthulhu mythos. Easy. Slight twist for part 2 - the dimensions are given in columns, not in rows.
#!/usr/bin/python3
INPUTFILE="03-input.txt"
#part 1
num_triangles=0
with open(INPUTFILE) as f:
for line in f:
sides=[int(i) for i in line.split()]
sides.sort()
if sides[0]+sides[1]>sides[2]:
num_triangles+=1
print("Part 1: ", num_triangles)
#part 2
triangles=[]
num_triangles=0
with open(INPUTFILE) as f:
lines=[]
for line in f:
lines.append([ int(i) for i in line.split() ])
if len(lines)>=3:
# process a triangle
triangles.extend([ lines[0][i], lines[1][i], lines[2][i] ] for i in range(3))
lines=[]
#print(triangles)
for sides in triangles:
#print(sides)
sides.sort()
if sides[0]+sides[1]>sides[2]:
num_triangles+=1
print("Part 2: ", num_triangles)