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小兔的叔叔从外面旅游回来给她带来了一个礼物，小兔高兴地跑回自己的房间，拆开一看是一个棋盘，小兔有所失望。不过没过几天发现了棋盘的好玩之处。从起点(0，0)走到终点(n,n)的最短路径数是C(2n,n),现在小兔又想如果不穿越对角线(但可接触对角线上的格点)，这样的路径数有多少?小兔想了很长时间都没想 阅读全文
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This is a small but ancient game. You are supposed to write down the numbers 1, 2, 3, . . . , 2n - 1, 2n consecutively in clockwise order on the groun 阅读全文
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Two positive integers are said to be relatively prime to each other if the Great Common Divisor (GCD) is 1. For instance, 1, 3, 5, 7, 9...are all rela 阅读全文
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Z城市居住着很多只跳蚤。在Z城市周六生活频道有一个娱乐节目。一只跳蚤将被请上一个高空钢丝的正中央。钢丝很长，可以看作是无限长。节目主持人会给该跳蚤发一张卡片。卡片上写有N+1个自然数。其中最后一个是M，而前N个数都不超过M，卡片上允许有相同的数字。跳蚤每次可以从卡片上任意选择一个自然数S，然后向左， 阅读全文
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Computing the exact number of ways that N things can be taken M at a time can be a great challenge when N and/or M become very large. Challenges are t 阅读全文
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In how many ways can you choose k elements out of n elements, not taking order into account? Write a program to compute this number. Input The input w 阅读全文
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The cows are having a picnic! Each of Farmer John's K (1 ≤ K ≤ 100) cows is grazing in one of N (1 ≤ N ≤ 1,000) pastures, conveniently numbered 1...N. 阅读全文