Uva 621 Secret Research

Secret Research 

At a certain laboratory results of secret research are thoroughly encrypted. A result of a single experiment is stored as an information of its completion:

`positive result', `negative result', `experiment failed' or `experiment not completed'

The encrypted result constitutes a string of digits S, which may take one of the following forms:

positive result 		 S = 1 or S = 4 or S = 78 

negative result 		 S = S35 

experiment failed 		 S = 9S4 

experiment not completed 		 S = 190S

(A sample result S35 means that if we add digits 35 from the right hand side to a digit sequence then we shall get the digit sequence corresponding to a failed experiment)

You are to write a program which decrypts given sequences of digits.

Input 

A integer n stating the number of encrypted results and then consecutive n lines, each containing a sequence of digits given as ASCII strings.

Output 

For each analysed sequence of digits the following lines should be sent to output (in separate lines):

		 + 		  for a positive result
		 - 		  for a negative result
		 * 		  for a failed experiment
		 ? 		  for a not completed experiment

In case the analysed string does not determine the experiment result, a first match from the above list should be outputted.

Sample Input 

4
78
7835
19078
944

Sample Output 

+
-
?
*

---

Miguel A. Revilla 
2000-01-10

 

 

 

#include<stdio.h>
#include<string.h>

char s[1002];

int main()
{
    int n, len;
    scanf("%d", &n);
    while(n--)
    {
        scanf("%s", s);
        len = strlen(s);
        if(strcmp(s, "1") == 0 || strcmp(s, "4") == 0 || strcmp(s, "78") == 0)
            printf("+\n");
        else if(s[len-1] == '5' && s[len-2] == '3') 
            printf("-\n");
        else if(s[0] == '9' && s[len-1] == '4')
            printf("*\n");
        else if(strstr(s, "190") != NULL && strstr(s, "190") - s == 0)
            printf("?\n");
    } 
    return 0;
}

解题思路：

我对这题感到无语，看题目就纠结了我很久了：

（个人观点）

1〉开始没有较为醒目的提示说明只能符合这四种情况的S，

2>中间括号对 S35 的解释表示不理解

3>在Output中最后一条语句表示不理解