Polygon area

# Read the number of vertices
n = int(input())

# Read the vertices
vertices = []
for _ in range(n):
    x, y = map(int, input().split())
    vertices.append((x, y))

# Close the polygon by appending the first vertex at the end
vertices.append(vertices[0])

# Calculate the double of the area using the Shoelace formula
area_double = 0
for i in range(n):
    x1, y1 = vertices[i]
    x2, y2 = vertices[i + 1]
    area_double += x1 * y2 - y1 * x2

# Output the absolute value of the doubled area
print(abs(area_double))

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED