18
04/2015
[LeetCode] Integer to Roman
Integer to Roman
Given an integer, convert it to a roman numeral.
Input is guaranteed to be within the range from 1 to 3999.
解题思路：
数字转罗马字符。并不是非常复杂，罗马字符的表示如维基百科所述http://zh.wikipedia.org/wiki/%E7%BD%97%E9%A9%AC%E6%95%B0%E5%AD%97。由于数字不多，可以直接用枚举法表示。代码如下：
class Solution {
public:
string intToRoman(int num) {
string qianwei[]={"", "M", "MM", "MMM"};
string baiwei[]={"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"};
string shiwei[]={"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"};
string gewei[] ={"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};
string result="";
result += qianwei[num/1000]; //千位
num = num%1000;
result += baiwei[num/100]; //百位
num = num%100;
result += shiwei[num/10]; //十位
num = num%10;
result += gewei[num]; //个位
return result;
}
};网上看到另一个比较好的解法，比我的解法要简练，代码如下：
class Solution {
public:
string intToRoman(int num) {
string str;
string symbol[]={"M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"};
int value[]= {1000,900,500,400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
for(int i=0;num!=0;++i)
{
while(num>=value[i])
{
num-=value[i];
str+=symbol[i];
}
}
return str;
}
};转载请注明：康瑞部落 » [LeetCode] Integer to Roman
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