# My C++ 28 ms solutions (no loop and no nested loop)

• I first write this no loop version:

``````class Solution {
public:
string intToRoman(int num) {
string s;
if (num >= 2000) {
s += "MM";
num -= 2000;
}
if (num >= 1000) {
s += "M";
num -= 1000;
}
if (num >= 900) {
s += "CM";
num -= 900;
}
if (num >= 500) {
s += "D";
num -= 500;
}
if (num >= 400) {
s += "CD";
num -= 400;
}
if (num >= 200) {
s += "CC";
num -= 200;
}
if (num >= 100) {
s += "C";
num -= 100;
}
if (num >= 90) {
s += "XC";
num -= 90;
}
if (num >= 50) {
s += "L";
num -= 50;
}
if (num >= 40) {
s += "XL";
num -= 40;
}
if (num >= 20) {
s += "XX";
num -= 20;
}
if (num >= 10) {
s += "X";
num -= 10;
}
if (num >= 9) {
s += "IX";
num -= 10;
}
if (num >= 5) {
s += "V";
num -= 5;
}
if (num == 4) {
s += "IV";
return s;
}
if (num >= 2) {
s += "II";
s -= 2;
}
if (num == 1)
s += "I";
return s;
}
};
``````

Then I clean it up with loop:

``````class Solution {
public:
string intToRoman(int num) {
static const int ns[] =   {2000,1000, 900,500, 400, 200,100,  90, 50,  40,  20, 10,  9,   5,   4,   2,  1};
static const char* ss[] = {"MM", "M","CM","D","CD","CC","C","XC","L","XL","XX","X","IX","V","IV","II","I"};
string s;
s.reverse(64);
for (auto i = 0; num > 0; ++i) {
if (num >= ns[i]) {
num -= ns[i];
s += ss[i];
}
}
return s;
}
};
``````

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