Careercup - Facebook面试题 - 6139456847347712

2014-05-01 01:50

题目链接

原题：

Microsoft Excel numbers cells as 1...26 and after that AA, AB.... AAA, AAB...ZZZ and so on. 
Given a number, convert it to that format and vice versa.

题目：微软的Office Excel对于每行每列的命名方式是1, 2, 3, ..., 26, AA, AB, ..., ZZ, AAA, ..., ZZZ。请写个函数完成这种“数字”和自然数的互相转换。

解法：数清楚每个长度“数字”的个数，然后分段转换即可。

代码：

// http://www.careercup.com/question?id=6139456847347712
#include <cstdio>
#include <iostream>
#include <string>
using namespace std;

string intToString(int n)
{
    string s = "";
    
    if (n <= 26) {
        while (n > 0) {
            s.push_back(n % 10 + '0');
            n /= 10;
        }
        reverse(s.begin(), s.end());
        return s;
    }

    int exp;
    int len;

    exp = 26;
    len = 1;
    while (n > exp) {
        n -= exp;
        ++len;
        exp *= 26;
    }

    --n;
    for (int i = 0; i < len; ++i) {
        s.push_back(n % 26 + 'A');
        n /= 26;
    }
    reverse(s.begin(), s.end());

    return s;
}

int stringToInt(const string &s)
{
    int n = 0;
    int len = (int)s.length();

    if (s[0] >= '0' && s[0] <= '9') {
        sscanf(s.c_str(), "%d", &n);
        return n;
    }

    int exp = 26;

    for (int i = 1; i < len; ++i) {
        n += exp;
        exp *= 26;
    }
    exp = 0;
    for (int i = 0; i < len; ++i) {
        exp = exp * 26 + (s[i] - 'A');
    }
    n += exp;
    ++n;

    return n;
}

int  main()
{
    int n;
    string s;
    
    while (scanf("%d", &n) == 1 && n > 0) {
        s = intToString(n);
        n = stringToInt(s);
        cout << n << ' ' << s << endl;
    }
    
    return 0;
}