其实不用思想太复杂，暴力枚举就行了……就乾乾64行，1165个字符而已……数组有亿点点长

#include<bits/stdc++.h>
using namespace std;
#define char string
char a[20]={"DA","D2","D3","D4","D5","D6","D7","D8","D9","DT","DJ","DQ","DK"},b[20]={"CA","C2","C3","C4","C5","C6","C7","C8","C9","CT","CJ","CQ","CK"},c[20]={"HA","H2","H3","H4","H5","H6","H7","H8","H9","HT","HJ","HQ","HK"},d[20]={"SA","S2","S3","S4","S5","S6","S7","S8","S9","ST","SJ","SQ","SK"};
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int f,s=0;
	cin>>f;
	char e;
	for(int i=0;i<f;i++){
		cin>>e;
		if(e[0]=='D'){
			for(int j=0;j<13;j++){
				if(a[j]==e){
					a[j]="01";
				}
			}
		}
		if(e[0]=='C'){
			for(int j=0;j<13;j++){
				if(b[j]==e){
				    b[j]="01";
				}
			}
		}
		if(e[0]=='H'){
			for(int j=0;j<13;j++){
				if(c[j]==e){
					c[j]="01";
				}
			}
		}
		if(e[0]=='S'){
			for(int j=0;j<13;j++){
				if(d[j]==e){
					d[j]="01";
				}
			}
		}
	}
	for(int j=0;j<13;j++){
		if(a[j]=="01"){
			s++;
		}
	}
	for(int j=0;j<13;j++){
		if(b[j]=="01"){
			s++;
		}
	}
	for(int j=0;j<13;j++){
		if(c[j]=="01"){
			s++;
		}
	}
	for(int j=0;j<13;j++){
		if(d[j]=="01"){
			s++;
		}
	}
	cout<<52-s;
	return 0;
}

去重，用52一减就好了

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	int s=52-n;
	for(int i=0;i<n;i++){
		string a;
		cin>>a;
		for(int j=i-1;j>0;j--){
			if(a[i]==a[j]&&a[j]!=' '&&a[i]!=' '){
				s++;
				a[j]=' ';
			}
		}
	}
	cout<<s<<endl;
	return 0;
}