给定字符串小写字母。任务是检查以任何可能的方式排列后，此字符串中字母的频率是否形成Recaman序列(不包括第一项)。
如果顺序打印，则打印“是”，否则输出“否”。
Recaman序列的几个起始术语是：
0, 1, 3, 6, 2, 7, 13, 20, 12, 21, 11, 22, 10, 23, 9, 24, 8 ….
注意：由于Recaman序列的第一项为零，因此不予考虑。
例子：
Input : str = "dddeweecceee"
Output : YES
Frequency of 'd' => 3
Frequency of 'e' => 6
Frequency of 'w' => 1
Frequency of 'c' => 2
These frequencies form the first 4 terms of
Recaman's sequence => {1, 3, 6, 2}
Input : str = "geeksforgeeks"
Output : NO
方法：
- 遍历字符串并将字符的频率存储在映射中。存储频率后，让地图的大小为N。
- 现在，创建一个数组，并在其中插入Recaman序列的前N个元素。
- 现在，遍历数组并检查数组的元素是否在map中作为键存在(不包括对零的检查) 。
- 如果映射中存在数组的每个元素，则输出“是”，否则输出“否”。
下面是上述方法的实现：
C++
// C++ program to check whether frequency of
// characters in a string makes
// Recaman Sequence
#include
using namespace std;
// Function to fill the array with first N numbers
// from Recaman's Sequence
int recaman(int arr[], int n)
{
// First term of the sequence is always 0
arr[0] = 0;
// Fill remaining terms using recursive
// formula
for (int i = 1; i <= n; i++) {
int temp = arr[i - 1] - i;
int j;
for (j = 0; j < i; j++) {
// If arr[i-1] - i is negative or
// already exists.
if ((arr[j] == temp) || temp < 0) {
temp = arr[i - 1] + i;
break;
}
}
arr[i] = temp;
}
}
// Function to check if the frequencies
// are in Recaman series
string isRecaman(string s)
{
// Store frequencies of characters
unordered_map m;
for (int i = 0; i < s.length(); i++)
m[s[i]]++;
// Get the size of the map
int n = m.size();
int arr[n + 1];
recaman(arr, n);
int flag = 1;
// Compare vector elements with values in Map
for (auto itr = m.begin(); itr != m.end(); itr++) {
int found = 0;
for (int j = 1; j <= n; j++) {
if (itr->second == arr[j]) {
found = 1;
break;
}
}
if (found == 0) {
flag = 0;
break;
}
}
if (flag == 1)
return "YES";
else
return "NO";
}
// Driver code
int main()
{
string s = "geeekkkkkkss";
cout << isRecaman(s);
return 0;
} Java
// Java program to check whether frequency of
// characters in a string makes Recaman Sequence
import java.util.HashMap;
import java.util.Map;
class GfG
{
// Function to fill the array with first
// N numbers from Recaman's Sequence
static void recaman(int arr[], int n)
{
// First term of the sequence is always 0
arr[0] = 0;
// Fill remaining terms using
// recursive formula
for (int i = 1; i <= n; i++)
{
int temp = arr[i - 1] - i;
for (int j = 0; j < i; j++)
{
// If arr[i-1] - i is negative or
// already exists.
if ((arr[j] == temp) || temp < 0)
{
temp = arr[i - 1] + i;
break;
}
}
arr[i] = temp;
}
}
// Function to check if the frequencies
// are in Recaman series
static String isRecaman(String s)
{
// Store frequencies of characters
HashMap m = new HashMap<>();
for (int i = 0; i < s.length(); i++)
if (m.containsKey(s.charAt(i)))
m.put(s.charAt(i), m.get(s.charAt(i))+1);
else
m.put(s.charAt(i), 1);
// Get the size of the map
int n = m.size();
int arr[] = new int[n + 1];
recaman(arr, n);
int flag = 1;
// Compare vector elements with values in Map
for (Map.Entry mapEle : m.entrySet())
{
int found = 0;
for (int j = 1; j <= n; j++)
{
if ((int)mapEle.getValue() == arr[j])
{
found = 1;
break;
}
}
if (found == 0)
{
flag = 0;
break;
}
}
if (flag == 1)
return "YES";
else
return "NO";
}
// Driver code
public static void main(String []args)
{
String s = "geeekkkkkkss";
System.out.println(isRecaman(s));
}
}
// This code is contributed by Rituraj Jain Python3
# Python3 program to check whether
# frequency of characters in a string
# makes Recaman Sequence
# Function to fill the array with first
# N numbers from Recaman's Sequence
def recaman(arr, n) :
# First term of the sequence
# is always 0
arr[0] = 0;
# Fill remaining terms using
# recursive formula
for i in range(1, n + 1) :
temp = arr[i - 1] - i;
for j in range(i) :
# If arr[i-1] - i is negative
# or already exists.
if ((arr[j] == temp) or temp < 0) :
temp = arr[i - 1] + i;
break;
arr[i] = temp;
# Function to check if the frequencies
# are in Recaman series
def isRecaman(s) :
# Store frequencies of characters
m = dict.fromkeys(list(s), 0);
for i in range(len(s)) :
m[s[i]] += 1;
# Get the size of the map
n = len(m);
arr = [0] * (n + 1);
recaman(arr, n);
flag = 1;
# Compare vector elements with
# values in Map
for keys in m.keys() :
found = 0;
for j in range(1, n + 1) :
if (m[keys] == arr[j]) :
found = 1;
break;
if (found == 0) :
flag = 0;
break;
if (flag == 1) :
return "YES";
else :
return "NO";
# Driver code
if __name__ == "__main__" :
s = "geeekkkkkkss";
print(isRecaman(s));
# This code is contributed by RyugaC#
// C# program to check whether frequency of
// characters in a string makes Recaman Sequence
using System;
using System.Collections.Generic;
class GFG
{
// Function to fill the array with first
// N numbers from Recaman's Sequence
public static void recaman(int[] arr, int n)
{
// First term of the sequence is always 0
arr[0] = 0;
// Fill remaining terms using
// recursive formula
for (int i = 1; i <= n; i++)
{
int temp = arr[i - 1] - i;
for (int j = 0; j < i; j++)
{
// If arr[i-1] - i is negative or
// already exists.
if ((arr[j] == temp) || temp < 0)
{
temp = arr[i - 1] + i;
break;
}
}
arr[i] = temp;
}
}
// Function to check if the frequencies
// are in Recaman series
public static String isRecaman(String s)
{
// Store frequencies of characters
Dictionary m = new Dictionary();
for (int i = 0; i < s.Length; i++)
{
if (m.ContainsKey(s[i]))
m[s[i]]++;
else
m.Add(s[i], 1);
}
// Get the size of the map
int n = m.Count;
int[] arr = new int[n + 1];
recaman(arr, n);
int flag = 1;
// Compare vector elements with values in Map
foreach (KeyValuePair mapEle in m)
{
int found = 0;
for (int j = 1; j <= n; j++)
{
if (mapEle.Value == arr[j])
{
found = 1;
break;
}
}
if (found == 0)
{
flag = 0;
break;
}
}
if (flag == 1)
return "YES";
else
return "NO";
}
// Driver code
public static void Main(String[] args)
{
String s = "geeekkkkkkss";
Console.WriteLine(isRecaman(s));
}
}
// This code is contributed by
// sanjeev2552 输出：
YES