Complete the Word CodeForces - 716B

字串挑战题解析
本文介绍了一道关于字串处理的编程挑战题,任务是判断一个含有未知字符(以问号表示)的字符串是否可以通过替换问号实现一个包含所有26个英文字母的连续子串。文章详细阐述了解决方案的思路与实现细节。

ZS the Coder loves to read the dictionary. He thinks that a word is nice if there exists a substring (contiguous segment of letters) of it of length 26 where each letter of English alphabet appears exactly once. In particular, if the string has length strictly less than 26, no such substring exists and thus it is not nice.

Now, ZS the Coder tells you a word, where some of its letters are missing as he forgot them. He wants to determine if it is possible to fill in the missing letters so that the resulting word is nice. If it is possible, he needs you to find an example of such a word as well. Can you help him?

Input

The first and only line of the input contains a single string s (1 ≤ |s| ≤ 50 000), the word that ZS the Coder remembers. Each character of the string is the uppercase letter of English alphabet ('A'-'Z') or is a question mark ('?'), where the question marks denotes the letters that ZS the Coder can't remember.

Output

If there is no way to replace all the question marks with uppercase letters such that the resulting word is nice, then print  - 1 in the only line.

Otherwise, print a string which denotes a possible nice word that ZS the Coder learned. This string should match the string from the input, except for the question marks replaced with uppercase English letters.

If there are multiple solutions, you may print any of them.

Example
Input
ABC??FGHIJK???OPQR?TUVWXY?
Output
ABCDEFGHIJKLMNOPQRZTUVWXYS
Input
WELCOMETOCODEFORCESROUNDTHREEHUNDREDANDSEVENTYTWO
Output
-1
Input
??????????????????????????
Output
MNBVCXZLKJHGFDSAQPWOEIRUYT
Input
AABCDEFGHIJKLMNOPQRSTUVW??M
Output
-1
Note

In the first sample case, ABCDEFGHIJKLMNOPQRZTUVWXYS is a valid answer beacuse it contains a substring of length 26 (the whole string in this case) which contains all the letters of the English alphabet exactly once. Note that there are many possible solutions, such as ABCDEFGHIJKLMNOPQRSTUVWXYZ or ABCEDFGHIJKLMNOPQRZTUVWXYS.

In the second sample case, there are no missing letters. In addition, the given string does not have a substring of length 26 that contains all the letters of the alphabet, so the answer is  - 1.

In the third sample case, any string of length 26 that contains all letters of the English alphabet fits as an answer.

题目大意:

  给出一个字符串,判断其是否存在一个子串(满足:包含26个英文字母且不重复,字串中有‘?’表示占位符可表示字母),如果存在则输出该字串‘?’位置用替换后的字母代替,其他不在子串中的‘?’用字母代替即可。如果该字串不存在满足条件的子串,则输出-1.

#include<stdio.h>
#include<string.h>
using namespace std;
const int N = 50005;
char str[N];
int vis[30];
int main(){
	while(scanf("%s",str)!=EOF){
		int len=strlen(str);
		int flag=1;
		if(len<26){
			printf("-1\n");
			continue;
		}
		memset(vis,0,sizeof(vis));
		for(int i=0;i<=len-26&&flag;i++){
			int cnt1=0,cnt2=0;
			memset(vis,0,sizeof(vis));
			for(int j=i;j<i+26;j++){
				if(str[j]=='?') cnt1++;
				else if(str[j]>='A'&&str[j]<='Z')
				     vis[str[j]-'A']++; 
			}
			for(int j=0;j<26;j++)
			   if(vis[j]==1) cnt2++;
			if(cnt1+cnt2==26){
				flag=0;
				int k=0;
				for(int j=i;j<i+26;j++){
					if(str[j]=='?'){
						for(;k<26;k++){
							if(!vis[k]){
								str[j]='A'+k;
								k++;
	                            break;
							}
						}
					}
				}
			}
		}
		for(int i=0;i<len;i++)
		    if(str[i]=='?') str[i]='Z';
		if(flag) printf("-1\n");
		else printf("%s\n",str);
	}
	return 0;
}


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