riverA = [[3,7], [3,9], [4,11], [6,12]]
riverB = [[12,4], [10,6], [6,7], [3,9], [2,4]]

# Part 1
totalA = 0
for i in range(len(riverA) - 1):
    dx = riverA[i+1][0] - riverA[i][0]
    dy = riverA[i+1][1] - riverA[i][1]
    dist = (dx ** 2 + dy ** 2) ** 0.5
    totalA += dist
    
totalB = 0
for i in range(len(riverB) - 1):
    dx = riverB[i+1][0] - riverB[i][0]
    dy = riverB[i+1][1] - riverB[i][1]
    dist = (dx ** 2 + dy ** 2) ** 0.5
    totalB += dist

print totalA, totalB

# Part 2
commonPoints = []
for point in riverA:
    if point in riverB:
        commonPoints.append(point)

print commonPoints