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palindrome.cpp
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palindrome.cpp
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#include <iostream>
#include <string>
#include <vector>
#include <set>
using namespace std;
bool isAPalindrome(const string & str) {
int start = 0;
int end = str.length()-1;
while( start <= end) {
if (str[start] != str[end]) {
return false;
}
++start;
--end;
}
return true;
}
/*
* Complete the function below.
*/
/*
* Complete the function below.
*/
int palindrome(string str) {
int n = str.length();
// Record the count of Palindromes
set<string> counter;
//Initialize the dp array
vector< vector<int> > dp(n, vector<int>(n,0));
//Every string of length 1 is a palindrome
for (unsigned int i = 0; i < dp.size(); ++i) {
dp[i][i] = 1;
counter.insert(string(1,str[i]));
}
//Consider each string length
for (unsigned int len = 2; len <= n; ++len) {
for (unsigned int start = 0; start < n - len + 1; ++start) {
unsigned int end = start + len -1;
if ((len == 2 && str[start] == str[end]) ||
(str[start] == str[end] && dp[start+1][end-1] == 1)) {
dp[start][end] = 1;
string pal = str.substr(start, len);
if (counter.find(pal) == counter.end()) {
counter.insert(pal);
}
}
}
}
return counter.size();
}
int main() {
cout<<palindrome("aabaa")<<endl;
//cout<<isAPalindrome("abba")<<endl;
//cout<<isAPalindrome("abcdba")<<endl;
}