Hust oj 2106 Genuine Messages（字符串）

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于 2016-05-25 13:47:57 发布

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本文链接：https://blog.youkuaiyun.com/Sara_YF/article/details/51497800

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本文介绍了一种用于验证间谍发送的电子消息真实性的算法。该算法通过检查每第三个相同字符是否被重复来判断消息是否经过正确变异，以此确保消息的真实性。文章提供了具体的实现代码。

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Genuine Messages

Time Limit: 1000 MS

Memory Limit: 32768 K

Total Submit: 45(29 users)

Total Accepted: 32(28 users)

Rating:

Special Judge: No

Description

To communicate with HQ, spies send electronic messages over the Information Superhighway using a protocol called SMTP (Secret Message Translation Protocol). To ensure that these messages are genuine and have not, for example, been sent by an evil adversary, every message is modified in such a way that it looks like there was noise on the communication line, or the sender was very nervous while typing the message. However, the mutation algorithm is carefully crafted such that an imposter is very unlikely to replicate this particular effect, and it is also easy for field agents to intentionally insert a “mistake” if they are forced at gunpoint to write a message.

In a correctly mutated message every third appearance of each letter is duplicated. For example, “HELLOTHEREEWELLLBEFINEE” is the correct mutation if the agent wanted to send “HELLOTHEREWELLBEFINE”. For the past few decades these messages have been checked by highly trained monkeys. Since the number of messages arriving at the HQ has greatly increased recently, they have tasked you with writing an automated program that can alert HQ when a message is definitely fake and not sent by our agent.

Input

On the first line one positive number: the number of test cases, at most 100.

After that per test case:

# one line with a string M (1 <= length(M) <= 100 000), consisting of uppercase letters only: the incoming message to check.

Output

Per test case:

# one line with either “OK” or “FAKE”, indicating whether or not the message M can be the result of a correctly applied mutation to some (unspecified) original message.

Sample Input

3
BAPC
AABA
ABCABCBBAAACC

Sample Output

OK
FAKE
OK

讲道理挺水一个字符串，读题读了半天，就是句子中相同的字母如果出现了三次，那么就再重复出现一次，因为着急WA了两发

#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;

const int maxn = 100005;
char a[maxn];
int ans[26];
int t;

int main()
{
    scanf("%d",&t);
    while(t--)
    {
        memset(ans,0,sizeof(ans));
        scanf("%s",&a);
        int len = strlen(a);
        int flag = 0;
        for(int i=0;i<len;i++)
        {
            ans[a[i]-'A']++;
            if(ans[a[i]-'A'] == 3)
            {
                if(a[i] != a[i+1])
                {
                    flag = 1;
                    break;
                }
                else
                    ans[a[i]-'A'] = -1;
            }
        }
        if(flag == 1)
            printf("FAKE\n");
        else
            printf("OK\n");
    }
    return 0;
}