# Check if a string can be split into substrings starting with N followed by N characters

Given a string str, the task is to check if it can be split into substrings such that each substring starts with a numeric value followed by a number of characters represented by that numeric integer.

Examples:

Input: str = “4g12y6hunter”
Output: Yes
Explanation:
Substrings “4g12y” and “6hunter” satisfy the given condition

Input: str = “31ba2a”
Output: No
Explanation:
The entire string cannot be split into substrings of desired types

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

Follow the steps below to solve the problem:

• Check for the conditions when a split is not possible:
• If the integer, in the beginning of a substring, is greater than the total number of succeeding characters in the remaining substring.
• If the above two condition are not satisfied, an answer is definitely possible. Hence find the substrings recursively.

Below is the implementation of the above approach:

## C++

 `// C++ Program to implement the ` `// above approach ` `#include ` `using` `namespace` `std; ` ` `  `// Function to check if the given ` `// can be split into desired ` `// substrings ` `bool` `helper(string& s, ``int` `pos) ` `{ ` `    ``// Length of the string ` `    ``int` `len = s.size(); ` ` `  `    ``if` `(pos >= len) ` `        ``return` `true``; ` ` `  `    ``if` `(!``isdigit``(s[pos])) ` `        ``return` `false``; ` ` `  `    ``int` `num = 0; ` ` `  `    ``// Traverse the string ` `    ``for` `(``int` `i = pos; i < len; i++) { ` ` `  `        ``// Extract the digit ` `        ``num = num * 10 + s[pos] - ``'0'``; ` ` `  `        ``// Check if the extracted number ` `        ``// does not exceed the remaining ` `        ``// length ` `        ``if` `(i + 1 + num > len) ` `            ``return` `false``; ` ` `  `        ``// Check for the remaining ` `        ``// string ` `        ``if` `(helper(s, i + 1 + num)) ` `            ``return` `true``; ` `    ``} ` ` `  `    ``// If generating desired ` `    ``// substrings is not possible ` `    ``return` `false``; ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``string s = ``"123abc4db1c"``; ` `    ``if` `(helper(s, 0)) ` `        ``cout << ``"Yes"``; ` `    ``else` `        ``cout << ``"No"``; ` `} `

## Java

 `// Java program to implement the  ` `// above approach  ` `import` `java.util.*; ` ` `  `class` `GFG{ ` `     `  `// Function to check if the given  ` `// can be split into desired  ` `// substrings  ` `public` `static` `boolean` `helper(String s, ``int` `pos)  ` `{  ` `     `  `    ``// Length of the string  ` `    ``int` `len = s.length();  ` `     `  `    ``if` `(pos >= len)  ` `        ``return` `true``;  ` `    ``if` `(!Character.isDigit(s.charAt(pos))) ` `        ``return` `false``;  ` `     `  `    ``int` `num = ``0``;  ` `     `  `    ``// Traverse the string  ` `    ``for``(``int` `i = pos; i < len; i++) ` `    ``{ ` `         `  `       ``// Extract the digit  ` `       ``num = num * ``10` `+ s.charAt(pos) - ``'0'``;  ` `        `  `       ``// Check if the extracted number  ` `       ``// does not exceed the remaining  ` `       ``// length  ` `       ``if` `(i + ``1` `+ num > len)  ` `           ``return` `false``;  ` `        `  `       ``// Check for the remaining  ` `       ``// string  ` `       ``if` `(helper(s, i + ``1` `+ num))  ` `           ``return` `true``;  ` `    ``}  ` `     `  `    ``// If generating desired  ` `    ``// substrings is not possible  ` `    ``return` `false``;  ` `}  ` ` `  `// Driver code ` `public` `static` `void` `main (String[] args) ` `{ ` `    ``String s = ``"123abc4db1c"``;  ` `     `  `    ``if` `(helper(s, ``0``))  ` `        ``System.out.print(``"Yes"``); ` `    ``else` `        ``System.out.print(``"No"``); ` `} ` `} ` ` `  `// This code is contributed by divyeshrabadiya07 `

## Python3

 `# Python3 program to implement the ` `# above approach ` ` `  `# Function to check if the given ` `# can be split into desired ` `# substrings ` `def` `helper(s, pos): ` `     `  `    ``# Length of the string ` `    ``size ``=` `len``(s) ` ` `  `    ``if``(pos >``=` `size): ` `        ``return` `True` ` `  `    ``if``(s[pos].isdigit() ``=``=` `False``): ` `        ``return` `False` ` `  `    ``num ``=` `0` ` `  `    ``# Traverse the string ` `    ``for` `i ``in` `range``(pos, size): ` `         `  `        ``# Extract the digit ` `        ``num ``=` `num ``*` `10` `+` `ord``(s[pos]) ``-` `48` ` `  `        ``# Check if the extracted number ` `        ``# does not exceed the remaining ` `        ``# length ` `        ``if` `(i ``+` `1` `+` `num > size): ` `            ``return` `False` ` `  `        ``# Check for the remaining ` `        ``# string ` `        ``if` `(helper(s, i ``+` `1` `+` `num)): ` `            ``return` `True` ` `  `    ``# If generating desired ` `    ``# substrings is not possible ` `    ``return` `False` ` `  `# Driver Code ` `s ``=` `"123abc4db1c"``; ` ` `  `if` `(helper(s, ``0``)): ` `    ``print``(``"Yes"``) ` `else``: ` `    ``print``(``"No"``) ` ` `  `# This code is contributed by Sanjit_Prasad `

## C#

 `// C# program to implement the  ` `// above approach  ` `using` `System; ` ` `  `class` `GFG{ ` `      `  `// Function to check if the given  ` `// can be split into desired  ` `// substrings  ` `public` `static` `bool` `helper(String s, ``int` `pos)  ` `{  ` `      `  `    ``// Length of the string  ` `    ``int` `len = s.Length;  ` `      `  `    ``if` `(pos >= len)  ` `        ``return` `true``;  ` `    ``if` `(!``char``.IsDigit(s[pos])) ` `        ``return` `false``;  ` `      `  `    ``int` `num = 0;  ` `      `  `    ``// Traverse the string  ` `    ``for``(``int` `i = pos; i < len; i++) ` `    ``{ ` `          `  `       ``// Extract the digit  ` `       ``num = num * 10 + s[pos] - ``'0'``;  ` `         `  `       ``// Check if the extracted number  ` `       ``// does not exceed the remaining  ` `       ``// length  ` `       ``if` `(i + 1 + num > len)  ` `           ``return` `false``;  ` `         `  `       ``// Check for the remaining  ` `       ``// string  ` `       ``if` `(helper(s, i + 1 + num))  ` `           ``return` `true``;  ` `    ``}  ` `      `  `    ``// If generating desired  ` `    ``// substrings is not possible  ` `    ``return` `false``;  ` `}  ` `  `  `// Driver code ` `public` `static` `void` `Main(String[] args) ` `{ ` `    ``String s = ``"123abc4db1c"``;  ` `      `  `    ``if` `(helper(s, 0))  ` `        ``Console.Write(``"Yes"``); ` `    ``else` `        ``Console.Write(``"No"``); ` `} ` `} ` ` `  `// This code is contributed by amal kumar choubey `

Output:

```Yes
```

Time Complexity: O(N)
Auxiliary Space: O(1)

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.