1040. Longest Symmetric String (25)
时间限制
400 ms
内存限制
65536 kB
代码长度限制
16000 B
判题程序
Standard
作者
CHEN, Yue
Given a string, you are supposed to output the length of the longest symmetric sub-string. For example, given “Is PAT&TAP symmetric?”, the longest symmetric sub-string is “s PAT&TAP s”, hence you must output 11.
Input Specification:
Each input file contains one test case which gives a non-empty string of length no more than 1000.
Output Specification:
For each test case, simply print the maximum length in a line.
Sample Input:
Is PAT&TAP symmetric?
Sample Output:
11
代码如下：
从开头出标记，从尾部开始遍历
#include<iostream>
#include<string>
using namespace std;
int main(){
string str;
getline(cin,str);
int maxlength=0;
for(int i=0;i<str.length();++i){
int flag=0;
for(int j=str.size()-1;j>=0;--j){
int indexi=i;
int indexj=j;
while(str[indexj]==str[indexi]&&indexi<=indexj){
int cha=indexj-indexi;
if(cha==0){
if(((indexi-i)*2+1)>maxlength){
flag=1;
maxlength=(indexi-i)*2+1;
}
break;
}else if(cha==1){
if(((indexj-i)*2)>maxlength){
flag=1;
maxlength=(indexj-i)*2;
}
break;
}
--indexj;++indexi;
}
if(flag==1) break;
}
}
printf("%d",maxlength);
return 0;
}
