LeetCode Integer to Roman

来源：互联网发布：战网安装不了传输数据编辑：程序博客网时间：2024/06/06 05:03

解题思路:首先要知道罗马数字是怎么去表示整数的,这里在维基百科上可以搜到,之后就直接枚举case就行了.

class Solution {public:    string intToRoman(int num) {        string res;        int flag[4];            flag[3] = num/1000;            num %= 1000;            if(flag[3])                res += string(flag[3],'M');            flag[2] = num/100;            num %= 100;            if(flag[2]){                if(flag[2] < 4)                res += string(flag[2],'C');                if(flag[2] == 4)                res += string(1,'C')+string(1,'D');                if(flag[2] == 9)                res += string(1,'C')+string(1,'M');                if(flag[2] == 5)                res += string(1,'D');                if(flag[2] > 5 && flag[2] < 9)                res += string(1,'D')+string(flag[2]-5,'C');            }            flag[1] = num/10;            num %= 10;            if(flag[1]){                if(flag[1] < 4)                res += string(flag[1],'X');                if(flag[1] == 4)                res += string(1,'X')+string(1,'L');                if(flag[1] == 9)                res += string(1,'X')+string(1,'C');                if(flag[1] == 5)                res += string(1,'L');                if(flag[1] > 5 && flag[1] < 9)                res += string(1,'L')+string(flag[1]-5,'X');            }            flag[0] = num;            if(flag[0]){                if(flag[0] < 4)                res += string(flag[0],'I');                if(flag[0] == 4)                res += string(1,'I')+string(1,'V');                if(flag[0] == 9)                res += string(1,'I')+string(1,'X');                if(flag[0] == 5)                res += string(1,'V');                if(flag[0] > 5 && flag[0] < 9)                res += string(1,'V')+string(flag[0]-5,'I');            }        return res;    }};

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