代码

#include<bits/stdc++.h>
#include<algorithm>
using namespace std;
const int MAXN=10010;
char str[MAXN],ans[MAXN];
int num=0;
void rever() {
	reverse(str,str+strlen(str));
	while (strlen(str)%5!=0) str[strlen(str)]='0';
	reverse(str,str+strlen(str));
} 
int main() {
	cin>>str;
	rever();
	int len=strlen(str);
	for (int i=0;i<len-4;i+=4) {
		int x=int(str[i]-48)*10000+int(str[i+1]-48)*1000+int(str[i+2]-48)*100+int(str[i+3]-48)*10+int(str[i+4]-48);
		switch (x) {
			case 0:
			 	ans[num]='0';
			 	break;
			case 1:
			 	ans[num]='1';
			 	break;
			case 10:
			 	ans[num]='2';
			 	break;
			case 11:
			 	ans[num]='3';
			 	break;
			case 100:
			 	ans[num]='4';
			 	break;
			case 101:
			 	ans[num]='5';
			 	break;
			case 110:
			 	ans[num]='6';
			 	break;
			case 111:
			 	ans[num]='7';
			 	break;
			case 1000:
			 	ans[num]='8';
			 	break;
			case 1001:
			 	ans[num]='9';
			 	break;
			case 1010:
			 	ans[num]='A';
			 	break;
			case 1011:
			 	ans[num]='B';
			 	break;
			case 1100:
			 	ans[num]='C';
			 	break;
			case 1101:
			 	ans[num]='D';
			 	break;
			case 1110:
			 	ans[num]='E';
			 	break;
			case 1111:
			 	ans[num]='F';
			 	break;
			case 10000:
			 	ans[num]='G';
			 	break;
			case 10001:
			 	ans[num]='H';
			 	break;
			case 10010:
			 	ans[num]='I';
			 	break;
			case 10011:
			 	ans[num]='J';
			 	break;
			case 10100:
			 	ans[num]='K';
			 	break;
			case 10101:
			 	ans[num]='L';
			 	break;
			case 10110:
			 	ans[num]='M';
			 	break;
			case 10111:
			 	ans[num]='N';
			 	break;
			case 11000:
			 	ans[num]='O';
			 	break;
			case 11001:
			 	ans[num]='P';
			 	break;
			case 11010:
			 	ans[num]='Q';
			 	break;
			case 11011:
			 	ans[num]='R';
			 	break;
			case 11100:
			 	ans[num]='S';
			 	break;
			case 11101:
			 	ans[num]='T';
			 	break;
			case 11110:
			 	ans[num]='U';
			 	break;
			case 11111:
			 	ans[num]='V';
			 	break;
		}
		num++;
	}
	cout<<ans;
	return 0;
}

样例全过但

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