Python O(n) no sorting
Solution 1:\npython\na = b = 10001\nc = d = 0\nfor num in nums:\n\tif num < a:\n\t\ta, b = num, a\n\telif num < b:\n\t\tb = num\n\tif num > c:\n\t\tc, d = num, 
**Solution 1:**\n``` python\na = b = 10001\nc = d = 0\nfor num in nums:\n\tif num < a:\n\t\ta, b = num, a\n\telif num < b:\n\t\tb = num\n\tif num > c:\n\t\tc, d = num, c\n\telif num > d:\n\t\td = num\nreturn c * d - a * b\n```\n\n**Solution 2:**\n``` python\na, b, c, d = sorted(nums[ : 4])\nfor num in nums[4 : ]:\n\tif num < a:\n\t\ta, b = num, a\n\telif num < b:\n\t\tb = num\n\telif num > d:\n\t\td, c = num, d\n\telif num > c:\n\t\tc = num\nreturn c * d - a * b\n```
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