#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int,int> ii;
typedef unsigned long long ull;

#define X first
#define Y second
#define pb push_back
#define mp make_pair
#define ep emplace_back
#define EL printf("\n")
#define sz(A) (int) A.size()
#define FOR(i,l,r) for (int i=l;i<=r;i++)
#define FOD(i,r,l) for (int i=r;i>=l;i--)
#define fillchar(a,x) memset(a, x, sizeof (a))
#define faster ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);


const int base = 1e9;
typedef vector<int> BigInt;

void Print(BigInt a) {
	printf("%d", a.back());
	FOD(i,a.size()-2,0) printf("%09d", a[i]);
	EL;
}

BigInt bigint(int x) {
	BigInt a;
	a.ep(x);
	return a;
}


BigInt operator + (BigInt a, BigInt b) {
	BigInt c;
	int v = 0;
	FOR(i, 0, max(a.size(), b.size()) - 1) {
		if (i < a.size()) v += a[i];
		if (i < b.size()) v += b[i];
		c.ep(v%base);
		v /= base;
	}
	if (v) c.ep(v);
	return c;
}

BigInt operator - (BigInt a, BigInt b) {
	BigInt c;
	int v = 0;
	FOR(i,0,a.size()-1) {
		v += a[i] - (i < b.size() ? b[i] : 0);
		if (v < 0) c.ep(v+base), v = -1;
		else c.ep(v), v = 0;
	}
	return c;
}

int main() {
//	freopen("INP.TXT", "r", stdin);
//  freopen("OUT.TXT", "w", stdout);

	char s[200];
	int n;
	BigInt F[200][200];
	scanf("%s\n", s);
	n = strlen(s)-1;

	FOD(i,n,0)
	FOR(j,i,n) {
		if (i == j) F[i][j] = bigint(1);
		else {
			if (i == j-1) {
				if (s[i] == s[j]) F[i][j] = bigint(3);
				else
					F[i][j] = bigint(2);
			} else {
				F[i][j] = F[i+1][j] + F[i][j-1] - F[i+1][j-1];
				if (s[i] == s[j])
					F[i][j] = F[i][j] + F[i+1][j-1] + bigint(1);
			}
		}
	}

	Print(F[0][n]);

	return 0;
}
by

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Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}