Submission #306864

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Source Code Expand

import itertools
n = int(raw_input())
xy = [map(int,raw_input().split()) for _ in range(n)]
exist = {x:{} for x,y in xy}
for x,y in xy:
    exist[x][y] = True
for xy1,xy2 in itertools.combinations(xy,2):
    x1,y1 = xy1
    x2,y2 = xy2
    x3,y3 = -(y2-y1)+x1, (x2-x1)+y1
    x4,y4 =  (y1-y2)+x2,-(x1-x2)+y2
    try:
        if exist[x3][y3] and exist[x4][y4]:
            ans = sorted([xy.index(xy1)+1,xy.index(xy2)+1,xy.index([x3,y3])+1,xy.index([x4,y4])+1])
            print 4
            print "\n".join(map(str,ans))
            break
    except:
        pass
else:
    print 0

Submission Info

Judge Result