Given a list of non negative integers, arrange them such that they form the largest number.
For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.
Note: The result may be very large, so you need to return a string instead of an integer.
C++代码实现：
#include<iostream> #include<string> #include<vector> using namespace std; class Solution { public: string largestNumber(vector<int> &num) { if(num.empty()) return ""; string ret; int i,j; while(!num.empty()) { i=0; for(j=1;j<(int)num.size();j++) { if((to_string(num[i])+to_string(num[j]))<(to_string(num[j])+to_string(num[i]))) i=j; } ret+=to_string(num[i]); num.erase(num.begin()+i); } while(ret.size()>1&&ret[0]=='0') ret.erase(ret.begin()); return ret; } }; int main() { Solution s; vector<int> vec={3,30,34,5,9}; cout<<s.largestNumber(vec)<<endl; }
直接调用STL算法进行排序：
#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
using namespace std;
//不能声明non-static成员函数
bool Mycmp(int n1,int n2)
{
string s1=to_string(n1);
string s2=to_string(n2);
return s1+s2>s2+s1;
}
class Solution
{
public:
string largestNumber(vector<int> &num)
{
if(num.empty())
return "";
string ret="";
sort(num.begin(),num.end(),Mycmp);
//sort(num.begin(),num.end(),[](int n1,int n2){ return to_string(n1)+to_string(n2)>to_string(n2)+to_string(n1);});
if(num[0]==0)
return "0";
for(auto a:num)
ret+=to_string(a);
return ret;
}
//声明为static成员是可以的
static bool Mycmp(int n1,int n2)
{
string s1=to_string(n1);
string s2=to_string(n2);
return s1+s2>s2+s1;
}
};
int main()
{
Solution s;
vector<int> num= {3,32,321};
cout<<s.largestNumber(num)<<endl;
}
