1027 Colors in Mars (20 分)（进制转换）

People in Mars represent the colors in their computers in a similar way as the Earth people. That is, a color is represented by a 6-digit number, where the first 2 digits are for Red, the middle 2 digits for Green, and the last 2 digits for Blue. The only difference is that they use radix 13 (0-9 and A-C) instead of 16. Now given a color in three decimal numbers (each between 0 and 168), you are supposed to output their Mars RGB values.

Input

Each input file contains one test case which occupies a line containing the three decimal color values.

Output

For each test case you should output the Mars RGB value in the following format: first output “#, then followed by a 6-digit number where all the English characters must be upper-cased. If a single color is only 1-digit long, you must print a “0” to the left.

Sample Input

15 43 71

Sample Output

#123456

题目大意：

给三个十进制的数，把它们转换为十三进制的数输出。要求在前面加上一个"#"号

分析：

因为0~168的十进制转换为13进制不会超过两位数，所以这个两位数为(num / 13)(num % 13)构成的数字

原文链接：https://blog.csdn.net/liuchuo/article/details/52120889

题解

1. 注意十进制数可能为0；
2. 注意十进制数转换为十三进制数可能只有1位，需要左边添0。

#include <bits/stdc++.h>

using namespace std;
string exchange(int a)
{
    string s;
    if(a==0) s="00";
    while(a){
        if(a%13==10) s+="A";
        else if(a%13==11) s+="B";
        else if(a%13==12) s+="C";
        else s+=a%13+'0';
        a/=13;
    }
    reverse(s.begin(),s.end());
    if(s.size()==1) s="0"+s;
    return s;
}
int main()
{
#ifdef ONLINE_JUDGE
#else
    freopen("1.txt", "r", stdin);
#endif
    int a,b,c;
    cin>>a>>b>>c;
    cout<<"#"+exchange(a)+exchange(b)+exchange(c);
    return 0;
}

本来觉得自己写的挺简洁的，直到看到柳神的代码Orz简洁之神！

#include <cstdio>
using namespace std;
int main() {
    char c[14] = {"0123456789ABC"};
    printf("#");
    for(int i = 0; i < 3; i++) {
        int num;
        scanf("%d", &num);
        printf("%c%c", c[num/13], c[num%13]);
    }
    return 0;
}