Leetcode 12. Integer to Roman

这道题就是先求出各个位上1~9的表示方法 然后进行拼接

public class Solution {
    public String intToRoman(int num) {
        String result = "";
        int shang = num / 1000;
        num = num % 1000;
        if (shang > 0) {
            for (int i = 0; i < shang; i++) {
                result = result + "M";
            }
        }
        
        shang = num / 100;
        num = num % 100;
        if (shang > 0) {
            if (shang == 9) {
                result = result + "CM";
            } else if (shang >= 5) {
                result = result + "D";
                shang = shang - 5;
                for (int i = 0; i < shang; i++) {
                    result = result + "C";
                }
            } else if (shang == 4) {
                result = result + "CD";
            } else {
                for (int i = 0; i < shang; i++) {
                    result = result + "C";
                }
            }
        }
        
        
        shang = num / 10;
        num = num % 10;
        
        if (shang > 0) {
            if (shang == 9) {
                result = result + "XC";
            } else if (shang >= 5) {
                result = result + "L";
                shang = shang - 5;
                for (int i = 0; i < shang; i++) {
                    result = result + "X";
                }
            } else if (shang == 4) {
                result = result + "XL";
            } else {
                for (int i = 0; i < shang; i++) {
                    result = result + "X";
                }
            }
        }
        
        shang = num;
        
        if (shang > 0) {
            if (shang == 9) {
                result = result + "IX";
            } else if (shang >= 5) {
                result = result + "V";
                shang = shang - 5;
                for (int i = 0; i < shang; i++) {
                    result = result + "I";
                }
            } else if (shang == 4) {
                result = result + "IV";
            } else {
                for (int i = 0; i < shang; i++) {
                    result = result + "I";
                }
            }
        }
        
        return result;
    }
}