Per recently learned about palindromes. Now he wants to tell us about it and also has more awesome scientific news to share with us.
“A palindrome is a word that is the same no matter whether you read it backward or forward”, Per recently said in an interview. He continued: “For example, add is not a palindrome, because reading it backwards gives dda and it’s actually not the same thing, you see. However, if we reorder the letters of the word, we can actually get a palindrome. Hence, we say that add is a Peragram, because it is an anagram of a palindrome”.
Per gives us a more formal definition of Peragrams: “Like I said, if a word is an anagram of at least one palindrome, we call it a Peragram. And recall that an anagram of a word w, possibly in a different order.”
Task
Given a string, find the minimum number of letters you have to remove from it, so that the string becomes a Peragram.
Input
Input consists of a string on a single line. The string will contain at least a-z.
Output
Output should consist of a single integer on a single line, the minimum number of characters that have to be removed from the string to make it a Peragram.
| Sample Input 1 | Sample Output 1 |
|---|---|
abc |
2 |
| Sample Input 2 | Sample Output 2 |
|---|---|
aab |
0 |
题意
问给出的字符串需要删除多少个字母后才能组成回文串
思路
相同字母个数是偶数的话才能构成回文，奇数字母只能有一个，所以只需要统计每个字母的个数，然后，答案就是个数为奇数的字母数-1
代码
#include<bits/stdc++.h> int vis[30]; char aa[1005]; int main() { while (~scanf("%s", aa)) { memset(vis, 0, sizeof(vis)); int len = strlen(aa); for (int i = 0; i < len; i++) { vis[aa[i] - 'a']++; } int ans = 0; for (int i = 0; i < 26; i++) { if (vis[i] % 2) { ans++; } } if (ans) ans--; printf("%d\n", ans); } return 0; }