1.If p is the perimeter of a right angle triangle with integral length sides, {a,b,c}, there are exactly three solutions for p = 120. click

{20,48,52}, {24,45,51}, {30,40,50}

For which value of p <=1000, is the number of solutions maximised

翻译过来就是：

如果p是这样一个数，满足三元组{a,b,c}之和是p，且a，b，c能组成直角三角形的三个边。当p=120的时候，且有三个解：

{20,48,52}, {24,45,51}, {30,40,50}

那么在p<=1000以内，满足以上条件的解的个数最多的p是几？

答案：840.

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2.A permutation is an ordered arrangement of objects. For example, 3124 is one possible permutation of the digits 1, 2, 3 and 4. If all of the permutations are listed numerically or alphabetically, we call it lexicographic order. The lexicographic permutations of 0, 1 and 2 are:

012 021 102 120 201 210

What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 click

翻译：A permutation is an ordered arrangement of objects。（大意就是排列的定义）比如，3124是数字1，2，3，4的一种可能排列。如果把所有的排列按照数字或者字母列出来，我们称为字典顺序。数字0，1，2的字典排序为：

012 021 102 120 201 210

那么数字0，1，2，3，4，5，6，7，8，9的字典排序的第1000000（100万）个排列数字是几？

答案：2783915460{ code placeholder}