Sort groups of numbers and characters separately in a String
Given string str of alphanumeric characters, the task is to sort the similar group of consecutive characters separately and print the modified string i.e. all consecutive groups of digits and alphabetical characters will be sorted separately.
Examples:
Input: str = “121geeks21”
Output: 112eegks12
Explaination: “121”, “geeks”, “21” are the valid groups
and they will be sorted separately.Input: str = “cba321ab”
Output: abc123ab
Approach: Create a vector to store the starting indices of all the valid groups in the given string. Now, traverse the string character by character and if the current character is from a different group than the previous character then push the current index to the vector. After the string has been traversed completely, sort all the individual groups of a substring of the given string using the vector updated earlier. Finally, print the modified string.
Below is the implementation of the above approach:
CPP
// C++ implementation of the approach #include <bits/stdc++.h> using namespace std; // Function to return the modified string string get_string(string str, int n) { // To store the previous character char prev = str[0]; // To store the starting indices // of all the groups vector< int > result; // Starting index of the first group result.push_back(0); for ( int i = 1; i < n; i++) { // If the current character and the // previous character differ if ( isdigit (str[i]) != isdigit (prev)) { // Push the starting index // of the new group result.push_back(i); } // The current character now becomes previous prev = str[i]; } // Sort the first group sort(str.begin(), str.begin() + result[0]); // Sort all the remaining groups for ( int i = 0; i < result.size() - 1; i++) { sort(str.begin() + result[i], str.begin() + result[i + 1]); } //cout<<str<<endl; // Sort the last group sort(str.begin() + result[result.size() - 1], str.end()); // Return the modified string return str; } // Driver code int main() { string str = "121geeks21" ; int n = str.length(); cout << get_string(str, n); return 0; } |
Python3
# Python 3 implementation of the approach # Function to return the modified string def get_string(st, n): # To store the previous character prev = st[ 0 ] # To store the starting indices # of all the groups result = [] # Starting index of the first group result.append( 0 ) for i in range ( 1 , n): # If the current character and the # previous character differ if (st[i].isdigit() ! = prev.isdigit()): # Push the starting index # of the new group result.append(i) # The current character now becomes previous prev = st[i] # Sort the first group st = list (st) st[:result[ 0 ]].sort() p = st.copy() # Sort all the remaining groups for i in range ( len (result) - 1 ): p[result[i]:result[i + 1 ]] = sorted (st[result[i]:result[i + 1 ]]) # print(''.join(st)) # Sort the last group p[ len (p) - 2 :] = sorted (st[result[ - 1 ]:]) # Return the modified string return ''.join(p) # Driver code if __name__ = = "__main__" : st = "121geeks21" n = len (st) print (get_string(st, n)) # This code is contributed by ukasp. |
112eegks12
Time complexity: O(n*nlogn)
Auxiliary Space: O(n)
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