HDU6342-2018ACM暑假多校联合训练4-1011-Problem K. Expression in Memories

Posted 2020-12-27 qq965921539

Problem K. Expression in Memories

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others)
Total Submission(s): 0    Accepted Submission(s): 0
Special Judge

Problem Description

Kazari remembered that she had an expression s0 before.
Definition of expression is given below in Backus–Naur form.
<expression> ::= <number> | <expression> <operator> <number>
<operator> ::= "+" | "*"
<number> ::= "0" | <non-zero-digit> <digits>
<digits> ::= "" | <digits> <digit>
<digit> ::= "0" | <non-zero-digit>
<non-zero-digit> ::= "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
For example, `1*1+1`, `0+8+17` are valid expressions, while +1+1, +1*+1, 01+001 are not.
Though s0 has been lost in the past few years, it is still in her memories. 
She remembers several corresponding characters while others are represented as question marks.
Could you help Kazari to find a possible valid expression s0 according to her memories, represented as s, by replacing each question mark in s with a character in 0123456789+* ?

 

 

Input

The first line of the input contains an integer T denoting the number of test cases.
Each test case consists of one line with a string s (1≤|s|≤500,∑|s|≤105).
It is guaranteed that each character of s will be in 0123456789+*? .

 

 

Output

For each test case, print a string s0 representing a possible valid expression.
If there are multiple answers, print any of them.
If it is impossible to find such an expression, print IMPOSSIBLE.

 

 

Sample Input

5

?????

0+0+0

?+*??

?0+?0

?0+0?

 

 

Sample Output

11111

0+0+0

IMPOSSIBLE

10+10

IMPOSSIBLE

题意就是让你在？里添加上合适的1或者+，并判断该式子是否合法（语序有一点错误）

注意在类似 +0? 的情况下， ? 须被替换为 + 或 * ，其余情况直接将 ? 替换为非零数字就好。替换完成后判断一下是否合法。

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 ———HDU题解

全靠队友一条大腿，当时WA到死都没找到0？？1这个错误

 1 #include<iostream>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 
 6 char ch[510];
 7 int ch1[510];
 8 int main()
 9 {
10     ios::sync_with_stdio(false);
11     int t;
12     cin >> t;
13     while (t--)
14     {
15         cin >> ch;
16         bool flag = 0;
17         for (int i = 0; i < strlen(ch); i++)
18         {
19             if (i > 1 && (ch[i - 2] == ‘+‘ || ch[i - 2] == ‘*‘) && ch[i - 1] == ‘0‘ && ch[i] == ‘?‘)
20                 ch[i] = ‘+‘;
21             if (i == 1 && ch[i] == ‘?‘ && ch[i - 1] == ‘0‘)
22                 ch[i] = ‘+‘;
23             else if(ch[i] == ‘?‘)
24                 ch[i] = ‘1‘;
25         }
26         if (ch[strlen(ch) - 1] == ‘+‘ || ch[strlen(ch) - 1] == ‘*‘ || ch[0] == ‘+‘ || ch[0] == ‘*‘)
27             flag = 1;
28         else
29         {
30             for (int i = 0; i < strlen(ch); i++)
31             {
32                 if (i == 1 && ch[i - 1] == ‘0‘ && ch[i] >= ‘0‘ && ch[i] <= ‘9‘)
33                     flag = 1;
34                 else if (i > 1 && ch[i - 1] == ‘0‘ && (ch[i - 2] == ‘+‘ || ch[i - 2] == ‘*‘) && ch[i] >= ‘0‘ && ch[i] <= ‘9‘)
35                     flag = 1;
36                 else if ((ch[i - 1] == ‘+‘ || ch[i - 1] == ‘*‘) && (ch[i] == ‘+‘ || ch[i] == ‘*‘))
37                     flag = 1;
38             }
39         }
40         if(flag)
41             cout << "IMPOSSIBLE" << endl;
42         else
43             cout << ch << endl;
44     }
45     return 0;
46 }