Lexicographically smallest numeric string having odd digit counts
Given a positive integer N, the task is to generate a lexicographically smallest numeric string of size N having an odd count of each digit.
Examples:
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Input: N = 4
Output: 1112
Explanation:
Digit 1 and 2 both have an even count and is the lexicographically smallest string possible.Input: N = 5
Output: 11111
Explanation:
Digit 1 has an odd count and is the lexicographically smallest string possible.
Approach: The given problem can be solved based on the observation that if the value of N is even, then the resulting string contains 1s, (N – 1) number of times followed by a single 2 is the smallest lexicographic string possible. Otherwise, the resulting string contains 1s, N number of times is the smallest lexicographic string possible.
Below is the implementation of the above approach:
C++14
// C++ program for the above approach#include <bits/stdc++.h>using namespace std;// Function to construct lexicographically// smallest numeric string having an odd// count of each charactersstring genString(int N){ // Stores the resultant string string ans = ""; // If N is even if (N % 2 == 0) { ans = string(N - 1, '1') + '2'; } // Otherwise else { ans = string(N, '1'); } return ans;}// Driver codeint main(){ int N = 5; cout << genString(N); return 0;} |
Python3
# python program for the above approach# Function to construct lexicographically# smallest numeric string having an odd# count of each charactersdef genString(N): # Stores the resultant string ans = "" # If N is even if (N % 2 == 0) : ans = "".join("1" for i in range(N-1)) ans = ans + "2" # Otherwise else : ans = "".join("1" for i in range(N)) return ans # Driver codeif __name__ == "__main__": N = 5 print(genString(N))# This code is contributed by anudeep23042002 |
C#
// C# program for the above approachusing System;class GFG { // Function to construct lexicographically // smallest numeric string having an odd // count of each characters static string genString(int N) { // Stores the resultant string string ans = ""; // If N is even if (N % 2 == 0) { for (int i = 0; i < N - 1; i++) ans += '1'; ans += '2'; } // Otherwise else { for (int i = 0; i < N; i++) ans += '1'; } return ans; } // Driver code public static void Main() { int N = 5; Console.WriteLine(genString(N)); }}// This code is contributed by ukasp. |
Javascript
<script> // JavaScript Program to implement // the above approach // Function to construct lexicographically // smallest numeric string having an odd // count of each characters function genString(N) { // Stores the resultant string let ans = ""; // If N is even if (N % 2 == 0) { ans = '1'.repeat(N - 1) + '2'; } // Otherwise else { ans = '1'.repeat(N); } return ans; } // Driver code let N = 5; document.write(genString(N)); // This code is contributed by Potta Lokesh </script> |
11111
Time Complexity: O(N)
Auxiliary Space: O(N)
