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?
翻譯過來就是：
如果p是這樣一個數，滿足三元組{a,b,c}之和是p，且a，b，c能組成直角三角形的三個邊。當p=120的時候，且有三個解：
{20,48,52}, {24,45,51}, {30,40,50}
那麼在p<=1000以內，滿足以上條件的解的個數最多的p是幾？
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
翻譯：A permutation is an ordered arrangement of objects。（大意就是排列的定義）比如，3124是數字1，2，3，4的一種可能排列。如果把所有的排列按照數字或者字母列出來，我們稱為字典順序。數字0，1，2的字典排序為：
012 021 102 120 201 210
那麼數字0，1，2，3，4，5，6，7，8，9的字典排序的第1000000（100萬）個排列數字是幾？
答案：2783915460{ code placeholder}
