题解

#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;
	cin>>s;
	char c1[10000],c2[10000],c3[100000],c4[10000];
	int n1=0,n2=0,n3=0,n4=0;
	for(int i = 0;i<(int)s.length();i++){
		if(s[i] >='0' && s[i] <= '9') c1[n1++] = s[i];
		else if(s[i] >='a' && s[i] <= 'z') c2[n2++] = s[i];
		else if(s[i] >='A' && s[i] <= 'Z') c3[n3++] = s[i];
		else c4[n4++] = s[i];
	}
	sort(c1,c1+n1);
	sort(c2,c2+n2);
	sort(c3,c3+n3);
	sort(c4,c4+n4);
	for(int i = 0;i<n2;i++) cout <<c2[i];
	for(int i = 0;i<n3;i++) cout <<c3[i];
	for(int i = 0;i<n1;i++) cout <<c1[i];
	for(int i = 0;i<n4;i++) cout <<c4[i];
	return 0;
}