Given a string with lowercase English alphabets. The task is to check whether the frequency of the characters in the string can be arranged as a Fibonacci series. If yes, print “YES”, otherwise print “NO”.
Note:
- Frequencies can be arranged in any way to form Fibonacci Series.
- The Fibonacci Series starts from 1. That is the series is 1,1,2,3,5,…..
Examples:
Input : str = "abeeedd" Output : YES Frequency of 'a' => 1 Frequency of 'b' => 1 Frequency of 'e' => 3 Frequency of 'd' => 2 These frequencies are first 4 terms of Fibonacci series => {1, 1, 2, 3} Input : str = "dzzddz" Output : NO Frequencies are not in Fibonacci series
Approach:
- Store the frequencies of each character of the string in a map. Let the size of the map be
after storing frequencies. - Then, make a vector and insert first ‘n’ elements of the Fibonacci series in this vector.
- Then, compare each element of the vector with values of the map. If both elements of vector and values of the map are same, print ‘YES’, otherwise print ‘NO’.
Below is the implementation of the above approach:
C++
// C++ program to check whether frequency of // characters in a string makes // Fibonacci Sequence #include <bits/stdc++.h> using namespace std;
int main() {
string s = "abeedddccccc" ;
// create a map to store the frequency of each character
map< char , int > freq;
for ( char c : s) {
freq++;
}
// create an array to store the frequency values
int f[freq.size()];
int i = 0;
for ( auto p : freq) {
f[i] = p.second;
i++;
}
// check if the frequency values form a Fibonacci sequence
int n = freq.size();
bool isFibonacci = true ;
sort(f, f + freq.size());
if (f[0] != 1 || f[1] != 1)
isFibonacci = false ;
else {
for ( int j = 2; j < n; j++) {
if (f[j] != f[j-1] + f[j-2]) {
isFibonacci = false ;
break ;
}
}
}
// print the result
if (isFibonacci) {
cout << "YES" << endl;
} else {
cout << "NO" << endl;
}
return 0;
} |
Java
// Java program to check whether frequency of // characters in a string makes // Fibonacci Sequence import java.util.HashMap;
import java.util.Vector;
class GFG
{ // Function to check if the frequencies
// are in Fibonacci series
static String isFibonacci(String s)
{
// map to store the
// frequencies of character
HashMap<Character,
Integer> m = new HashMap<>();
for ( int i = 0 ; i < s.length(); i++)
m.put(s.charAt(i),
m.get(s.charAt(i)) == null ? 1 :
m.get(s.charAt(i)) + 1 );
// Vector to store first n
// fibonacci numbers
Vector<Integer> v = new Vector<>();
// Get the size of the map
int n = m.size();
// a and b are first and second terms of
// fibonacci series
int a = 1 , b = 1 ;
int c;
v.add(a);
v.add(b);
// vector v contains elements of
// fibonacci series
for ( int i = 0 ; i < n - 2 ; i++)
{
v.add(a + b);
c = a + b;
a = b;
b = c;
}
int flag = 1 ;
int i = 0 ;
// Compare vector elements with values in Map
for (HashMap.Entry<Character,
Integer> entry : m.entrySet())
{
if (entry.getValue() != v.elementAt(i))
{
flag = 1 ;
break ;
}
i++;
}
if (flag == 1 )
return "YES" ;
else
return "NO" ;
}
// Driver Code
public static void main(String[] args)
{
String s = "abeebbbccccc" ;
System.out.println(isFibonacci(s));
}
} // This code is contributed by // sanjeev2552 |
Python3
# Python3 program to check whether the frequency # of characters in a string make Fibonacci Sequence from collections import defaultdict
# Function to check if the frequencies # are in Fibonacci series def isFibonacci(s):
# map to store the frequencies of character
m = defaultdict( lambda : 0 )
for i in range ( 0 , len (s)):
m[s[i]] + = 1
# Vector to store first n fibonacci numbers
v = []
# Get the size of the map
n = len (m)
# a and b are first and second
# terms of fibonacci series
a = b = 1
v.append(a)
v.append(b)
# vector v contains elements of
# fibonacci series
for i in range ( 0 , n - 2 ):
v.append(a + b)
c = a + b
a, b = b, c
flag, i = 1 , 0
# Compare vector elements with values in Map
for itr in sorted (m):
if m[itr] ! = v[i]:
flag = 0
break
i + = 1
if flag = = 1 :
return "YES"
else :
return "NO"
# Driver code if __name__ = = "__main__" :
s = "abeebbbccccc"
print (isFibonacci(s))
# This code is contributed by Rituraj Jain |
C#
// C# program to check whether frequency of // characters in a string makes // Fibonacci Sequence using System;
using System.Collections.Generic;
class GFG
{ // Function to check if the frequencies
// are in Fibonacci series
static String isFibonacci(String s)
{
// map to store the
// frequencies of character
int i = 0;
Dictionary< int ,
int > mp = new Dictionary< int ,
int >();
for (i = 0; i < s.Length; i++)
{
if (mp.ContainsKey(s[i]))
{
var val = mp[s[i]];
mp.Remove(s[i]);
mp.Add(s[i], val + 1);
}
else
{
mp.Add(s[i], 1);
}
}
// List to store first n
// fibonacci numbers
List< int > v = new List< int >();
// Get the size of the map
int n = mp.Count;
// a and b are first and second terms of
// fibonacci series
int a = 1, b = 1;
int c;
v.Add(a);
v.Add(b);
// vector v contains elements of
// fibonacci series
for (i = 0; i < n - 2; i++)
{
v.Add(a + b);
c = a + b;
a = b;
b = c;
}
int flag = 1;
// Compare vector elements with values in Map
foreach (KeyValuePair< int , int > entry in mp)
{
if (entry.Value != v[i])
{
flag = 1;
break ;
}
i++;
}
if (flag == 1)
return "YES" ;
else
return "NO" ;
}
// Driver Code
public static void Main(String[] args)
{
String s = "abeebbbccccc" ;
Console.WriteLine(isFibonacci(s));
}
} // This code is contributed by 29AjayKumar |
Javascript
<script> // Javascript program to check whether frequency of // characters in a string makes // Fibonacci Sequence // Function to check if the frequencies // are in Fibonacci series function isFibonacci(s)
{ // map to store the
// frequencies of character
var m = new Map();
for ( var i = 0; i < s.length; i++) {
if (m.has(s[i]))
{
m.set(s[i], m.get(s[i]));
}
else
{
m.set(s[i], 1);
}
}
// Vector to store first n
// fibonacci numbers
var v = [];
// Get the size of the map
var n = m.length;
// a and b are first and second terms of
// fibonacci series
var a = 1, b = 1;
var c;
v.push(a);
v.push(b);
// vector v contains elements of fibonacci series
for ( var i = 0; i < n - 2; i++) {
v.push(a + b);
c = a + b;
a = b;
b = c;
}
var flag = 1;
var i = 0;
// Compare vector elements with values in Map
m.forEach((value, key) => {
if (value != v[i]) {
flag = 0;
}
});
if (flag == 1)
return "YES" ;
else
return "NO" ;
} // Driver code var s = "abeeedd" ;
document.write( isFibonacci(s)); </script> |
Output
YES
Complexity Analysis:
- Time Complexity: O(n), where n is the length of the given string.
- Auxiliary Space: O(n)