• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>
            posts - 195,  comments - 30,  trackbacks - 0

            Encoding schemes are often used in situations requiring encryption or information storage/transmission economy. Here, we develop a simple encoding scheme that encodes particular types of words with five or fewer (lower case) letters as integers.

            Consider the English alphabet {a,b,c,...,z}. Using this alphabet, a set of valid words are to be formed that are in a strict lexicographic order. In this set of valid words, the successive letters of a word are in a strictly ascending order; that is, later letters in a valid word are always after previous letters with respect to their positions in the alphabet list {a,b,c,...,z}. For example,

            abc aep gwz

            are all valid three-letter words, whereas

            aab are cat

            are not.

            For each valid word associate an integer which gives the position of the word in the alphabetized list of words. That is:

                a -> 1
            b -> 2
            .
            .
            z -> 26
            ab -> 27
            ac -> 28
            .
            .
            az -> 51
            bc -> 52
            .
            .
            vwxyz -> 83681

            Your program is to read a series of input lines. Each input line will have a single word on it, that will be from one to five letters long. For each word read, if the word is invalid give the number 0. If the word read is valid, give the word's position index in the above alphabetical list.

            Input

            The input consists of a series of single words, one per line. The words are at least one letter long and no more that five letters. Only the lower case alphabetic {a,b,...,z} characters will be used as input. The first letter of a word will appear as the first character on an input line.

            The input will be terminated by end-of-file.

            Output

            The output is a single integer, greater than or equal to zero (0) and less than or equal 83681. The first digit of an output value should be the first character on a line. There is one line of output for each input line.

            Sample Input

            z
            a
            cat
            vwxyz

            Sample Output

            26
            1
            0
            83681

             

            利用組合數學定理
            {1,2,3,--,n}的r組合a1,a2,--,ar出現在{1,2,--,n}的r組合的字典序中的位置號如下:

            C(n,r)-C(n-a1,r)-C(n-a2,r-1)-------C(n-ar-1,2)-C(n-ar,1):證明略;

            組合數C(n,r)計算利用pascal公式。C(n+1,k)=C(n,k-1)+C(n,k)
            posted on 2009-07-18 10:08 luis 閱讀(380) 評論(0)  編輯 收藏 引用 所屬分類: 組合數學
            <2009年7月>
            2829301234
            567891011
            12131415161718
            19202122232425
            2627282930311
            2345678

            常用鏈接

            留言簿(3)

            隨筆分類

            隨筆檔案

            文章分類

            文章檔案

            友情鏈接

            搜索

            •  

            最新評論

            閱讀排行榜

            評論排行榜

            久久综合九色综合久99| 久久久国产精品福利免费| 久久精品国产欧美日韩99热| 色播久久人人爽人人爽人人片AV| 亚洲第一极品精品无码久久| 99久久精品国产一区二区| 97精品伊人久久大香线蕉| 精品久久久无码人妻中文字幕豆芽| 国产精品18久久久久久vr| 亚洲日韩欧美一区久久久久我| 久久亚洲精品国产精品| 久久久久国色AV免费观看| 国产精品久久久久…| 一本色道久久88—综合亚洲精品| 国产成人无码久久久精品一| 伊人热热久久原色播放www| 久久精品国产亚洲麻豆| 久久免费的精品国产V∧| 色天使久久综合网天天| 国产精品免费久久久久影院| 中文字幕久久久久人妻| 午夜精品久久影院蜜桃 | 欧美日韩精品久久久免费观看| 久久久久人妻一区精品色 | 久久这里有精品| 国产999精品久久久久久| 99久久婷婷免费国产综合精品| 色综合久久久久综合体桃花网| 无码乱码观看精品久久| 欧美激情精品久久久久久久九九九| 亚洲国产精品久久66| 香蕉久久夜色精品国产小说| 久久国产高清字幕中文| 国产成人精品久久二区二区| 91精品国产综合久久久久久| 久久精品人人槡人妻人人玩AV | 国产福利电影一区二区三区久久老子无码午夜伦不 | 99久久婷婷免费国产综合精品| 日韩精品久久无码人妻中文字幕| 日韩乱码人妻无码中文字幕久久| 无码精品久久久久久人妻中字|