10 lines
244 B
Python
10 lines
244 B
Python
axis = []
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for _ in range(int(input())) :
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axis.append(tuple(map(int, input().split())))
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axis.append(axis[0])
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area = 0
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for i in range(len(axis)-1) :
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area += axis[i][0]*axis[i+1][1] - axis[i][1]*axis[i+1][0]
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print(round(abs(area)*0.5,1)) |