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题意 在一个字符串中插入一个字母使其变成一个回文串 可以的话输出这个回文串 否则NA
大水题 插入情况最多就26*11种 可以直接暴力
#include<cstdio>
#include<cstring>
using namespace std;
const int N = 20;
char s[N], p[N];
int l;
bool ispal()
{
for(int i = 0; i < (l + 1) / 2; ++i)
if(p[i] != p[l - i]) return false;
return true;
}
int main()
{
int i, j, k;
scanf("%s", s);
l = strlen(s);
for(char c = 'a'; c <= 'z'; ++c)
{
for(k = 0; k <= l; ++k)
{
i = j = -1;
while(i < k - 1) p[++j] = s[++i];
p[++j] = c;
while(i < l - 1) p[++j] = s[++i];
if(ispal())
{
printf("%s\n", p);
return 0;
}
}
}
printf("NA\n");
return 0;
}
You can choose any lowercase English letter, and insert it to any position of s, possibly to the beginning or the end of s. You have to insert a letter even if the given string is already a palindrome.
If it is possible to insert one lowercase English letter into s so that the resulting string will be a palindrome, print the string after the insertion. Otherwise, print "NA" (without quotes, case-sensitive). In case there is more than one palindrome that can be obtained, you are allowed to print any of them.
The only line of the input contains a string s (1?≤?|s|?≤?10). Each character in s is a lowercase English letter.
If it is possible to turn s into a palindrome by inserting one lowercase English letter, print the resulting string in a single line. Otherwise, print "NA" (without quotes, case-sensitive). In case there is more than one solution, any of them will be accepted.
revive
reviver
ee
eye
kitayuta
NA
CF 505A Mr. Kitayuta's Gift(暴力)
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原文地址：http://blog.csdn.net/acvay/article/details/42869059
