ALGORITHM
1.Initialize another string B= A(given string)
2.Reverse String B
3. Find common subsequence between A and B.
int Solution::solve(string A) {
int n=A.length();
string B=A;
reverse(B.begin(),B.end());
int dp[n+1][n+1];
for(int i=0;i<=n;i++)
{
for(int j=0;j<=n;j++)
{
if(i==0 || j==0)
dp[i][j]=0;
else if(A[i-1]==B[j-1])
dp[i][j]=1+dp[i-1][j-1];
else
dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
}
}
return dp[n][n];
}