• ``````string inttostring(int &i)
{
string s;
stringstream ss(s);
ss << i;
return ss.str();
}
bool comp(const string &s1, const string &s2)
{
string s3 = s1 + s2;
string s4 = s2 + s1;
if(s3 >= s4)
return true;
else
return false;
}
class Solution {
public:
string largestNumber(vector<int> &num) {
int size = num.size();
vector<string> string1;
string result;
int tag = 0;
for(int i = 1; i <= size; i++) {
tag += num[i-1];
string temp = inttostring(num[i-1]);
string1.push_back(temp);
}
if(tag==0)
return "0";
std::sort(string1.begin(), string1.end(),comp);
for(int i=0; i<size;i++)
result += string1[i];
return result;

}

};``````

• Basically the same idea, just less code and better check, when we get only zero numbers.

``````  class Solution {
public:
string largestNumber(vector<int> &num) {

int n = num.size();
vector<string> numstrs(n);

for(int i = 0; i < n; i++)
{
numstrs[i] = to_string(num[i]); // to_string() is standard lib func
}

sort(numstrs.begin(), numstrs.end(), myCompare);

if (numstrs[n-1] == "0")
{
return "0";
}

string res;
for(int i = n-1; i >= 0; i--)
{
res += numstrs[i];
}

return res;
}

static bool myCompare (string str1, string str2)
{
return (str1 + str2) < (str2 + str1);
}
};``````

• Looks good. But I just wanted to add that your last piece of code, where you do "res += numstrs" could be slow for large inputs. You could make it even faster by using stringstream or reserving space ahead of time.

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