Palindromes+string+reverse()函数

本博客介绍了一个简单的程序,用于判断给定的字符串是否为回文串。程序通过直接使用库函数将字符串逆序并比较来实现这一功能。

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Palindromes

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2317    Accepted Submission(s): 1375


Problem Description
Write a program to determine whether a word is a palindrome. A palindrome is a sequence of characters that is identical to the string when the characters are placed in reverse order. For example, the following strings are palindromes: “ABCCBA”, “A”, and “AMA”. The following strings are not palindromes: “HELLO”, “ABAB” and “PPA”.
 

Input
The input file will consist of up to 100 lines, where each line contains at least 1 and at most 52 characters. Your program should stop processing the input when the input string equals “STOP”. You may assume that input file consists of exclusively uppercase letters; no lowercase letters, punctuation marks, digits, or whitespace will be included within each word.
 

Output
A single line of output should be generated for each string. The line should include “#”, followed by the problem number, followed by a colon and a space, followed by the string “YES” or “NO”.
 

Sample Input
ABCCBA A HELLO ABAB AMA ABAB PPA STOP
 

Sample Output
#1: YES #2: YES #3: NO #4: NO #5: YES #6: NO #7: NO
/*思路:直接用reverse()库函数将字符串逆序,判断是否相等*/
 
#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
int main()
{
	string a;
	int count=1;
	while(cin>>a&&a!="STOP"){
		cout<<"#"<<count++<<": ";
		string b=a;
		reverse(b.begin(),b.end());
		if(a==b)
			cout<<"YES"<<endl;
		else
			cout<<"NO"<<endl;
	}
	return 0;
}

# P1217 [USACO1.5] 回文质数 Prime Palindromes ## 题目描述 因为 $151$ 既是一个质数又是一个回文数(从左到右和从右到左是看一样的),所以 $151$ 是回文质数。 写一个程序来找出范围 $[a,b] (5 \le a < b \le 100,000,000)$(一亿)间的所有回文质数。 ## 输入格式 第一行输入两个正整数 $a$ 和 $b$。 ## 输出格式 输出一个回文质数的列表,一行一个。 ## 输入输出样例 #1 ### 输入 #1 ``` 5 500 ``` ### 输出 #1 ``` 5 7 11 101 131 151 181 191 313 353 373 383 ``` ## 说明/提示 Hint 1: Generate the palindromes and see if they are prime. 提示 1: 找出所有的回文数再判断它们是不是质数(素数). Hint 2: Generate palindromes by combining digits properly. You might need more than one of the loops like below. 提示 2: 要产生正确的回文数,你可能需要几个像下面这样的循环。 题目翻译来自NOCOW。 USACO Training Section 1.5 产生长度为 $5$ 的回文数: ```cpp for (d1 = 1; d1 <= 9; d1+=2) { // 只有奇数才会是素数 for (d2 = 0; d2 <= 9; d2++) { for (d3 = 0; d3 <= 9; d3++) { palindrome = 10000*d1 + 1000*d2 +100*d3 + 10*d2 + d1;//(处理回文数...) } } } ``` 以下是我的代码,请补充并改正: #include <bits/stdc++.h> using namespace std; int f1(int n){ for(int i=5;i<=pow(n,0.5);i++){ if((n%i==0)&&(n!=i)) return 0; } return 1; } int f2(int n){ string s=to_string(n); int left = 0, right = s.length() - 1; while (left < right) { if (s[left] != s[right]) { return 0; } left++; right--; } return 1; } int main() { int a,b;cin>>a>>b; for(int i=a;i<=b;i++){ } return 0; }
最新发布
07-29
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