12. Integer to Roman

12. Integer to Roman

char s[100];
char* intToRoman(int num) {
    char rs[] = "MDCLXVI";
    int ts[] = { 1000,500,100,50,10,5,1 };
    int cnt = 0;
    while(num){
        int i = 0;
        while(ts[i] > num) i++;
        if(i && num >= 4*ts[i]){
            s[cnt++] = rs[i];
            s[cnt++] = rs[i-1];
            num -= 4*ts[i];
        }
        else if(i && i+1 < 7 && ts[i] == 5*ts[i+1] && num >= ts[i]+ts[i+1]*4){
            s[cnt++] = rs[i+1];
            s[cnt++] = rs[i-1];
            num -= ts[i] + ts[i+1]*4;
        }
        else{
            int n = num / ts[i];
            num -= n*ts[i];
            while(n--) s[cnt++] = rs[i];
        }
    }
    s[cnt] = 0;
    return s;
}