Given N segments as ranges [L, R] where ranges are non-intersecting and non-overlapping. The task is to find all number between 1 to M that doesn’t belong to any of the given ranges.
Examples:
Input : N = 2, M = 6
Ranges:
[1, 2]
[4, 5]
Output : 3, 6
Explanation: Only 3 and 6 are missing from
the above ranges.
Input : N = 1, M = 5
Ranges:
[2, 4]
Output : 1, 5
Approach: Given that we have N ranges, which are non-overlapping and non-intersecting. First of all, sort all segments based on starting value. After sorting, iterate from each segment and find the numbers which are missing.
Algorithm:
Step 1: Start
Step 2: Create a class called Pair and make a constructor which takes two integer values as parameters.
Step 3: Create a static function that takes two parameters as input one in ArrayList of type Pair and the second an integer value.
Step 4: Now sort the given ArrayList using the collections sort method and use a comparator if two values are equal then will sort on the basis of the ending point.
Step 5: Now create an ArrayList called ans to store our answer
Step 6: Initialize a prev variable’s value to 0, Using a for-loop iterate across each range, saying for each range: first Create start and end variables from the place where it begins and ends.
, second Using a for-loop to iterate over all integers between prev and start, determine whether any elements are missing, and add those that are to the ans ArrayList, third Change prev to end.
Step 7: Start a for-loop, and iterate through each number between prev and m to see if there are any missing elements. If there are, add each one to the ans ArrayList.
Lastly, output any values that are less than or equal to m after iterating through the ans ArrayList.
Step 8: End
Below is the implementation of the above approach:
C++
// C++ program to find missing elements// from given Ranges#include <bits/stdc++.h>using namespace std;// Function to find missing elements// from given Rangesvoid findMissingNumber(vector<pair<int, int> > ranges, int m){ // First of all sort all the given ranges sort(ranges.begin(), ranges.end()); // store ans in a different vector vector<int> ans; // prev is use to store end of // last range int prev = 0; // j is used as a counter for ranges for (int j = 0; j < ranges.size(); j++) { int start = ranges[j].first; int end = ranges[j].second; for (int i = prev + 1; i < start; i++) ans.push_back(i); prev = end; } // for last segment for (int i = prev + 1; i <= m; i++) ans.push_back(i); // finally print all answer for (int i = 0; i < ans.size(); i++) { if (ans[i] <= m) cout << ans[i] << " "; }}// Driver codeint main(){ int N = 2, M = 6; // Store ranges in vector of pair vector<pair<int, int> > ranges; ranges.push_back({ 1, 2 }); ranges.push_back({ 4, 5 }); findMissingNumber(ranges, M); return 0;} |
Java
// Java program to find missing elements// from given Rangesimport java.util.ArrayList;import java.util.Collections;import java.util.Comparator;class GFG{static class Pair{ int first, second; public Pair(int first, int second) { this.first = first; this.second = second; }}// Function to find missing elements// from given Rangesstatic void findMissingNumber(ArrayList<Pair> ranges, int m) { // First of all sort all the given ranges Collections.sort(ranges, new Comparator<Pair>() { public int compare(Pair first, Pair second) { if (first.first == second.first) { return first.second - second.second; } return first.first - second.first; } }); // Store ans in a different vector ArrayList<Integer> ans = new ArrayList<>(); // prev is use to store end of // last range int prev = 0; // j is used as a counter for ranges for(int j = 0; j < ranges.size(); j++) { int start = ranges.get(j).first; int end = ranges.get(j).second; for(int i = prev + 1; i < start; i++) ans.add(i); prev = end; } // For last segment for(int i = prev + 1; i <= m; i++) ans.add(i); // Finally print all answer for(int i = 0; i < ans.size(); i++) { if (ans.get(i) <= m) System.out.print(ans.get(i) + " "); }}// Driver codepublic static void main(String[] args){ int N = 2, M = 6; // Store ranges in vector of pair ArrayList<Pair> ranges = new ArrayList<>(); ranges.add(new Pair(1, 2)); ranges.add(new Pair(4, 5)); findMissingNumber(ranges, M);}}// This code is contributed by sanjeev2552 |
Python3
# Python3 program to find missing # elements from given Ranges # Function to find missing elements # from given Ranges def findMissingNumber(ranges, m): # First of all sort all the # given ranges ranges.sort() # store ans in a different vector ans = [] # prev is use to store end # of last range prev = 0 # j is used as a counter for ranges for j in range(len(ranges)): start = ranges[j][0] end = ranges[j][1] for i in range(prev + 1, start): ans.append(i) prev = end # for last segment for i in range(prev + 1, m + 1): ans.append(i) # finally print all answer for i in range(len(ans)): if ans[i] <= m: print(ans[i], end = " ") # Driver Codeif __name__ == "__main__": N, M = 2, 6 # Store ranges in vector of pair ranges = [] ranges.append([1, 2]) ranges.append([4, 5]) findMissingNumber(ranges, M) # This code is contributed # by Rituraj Jain |
C#
// C# program to find missing elements// from given Rangesusing System;using System.Collections;using System.Collections.Generic;class GFG{ class sortHelper : IComparer{ int IComparer.Compare(object a, object b) { Pair first = (Pair)a; Pair second = (Pair)b; if (first.first == second.first) { return first.second - second.second; } return first.first - second.first; }} public class Pair{ public int first, second; public Pair(int first, int second) { this.first = first; this.second = second; }} // Function to find missing elements// from given Rangesstatic void findMissingNumber(ArrayList ranges, int m) { IComparer myComparer = new sortHelper(); ranges.Sort(myComparer); // Store ans in a different vector ArrayList ans = new ArrayList(); // prev is use to store end of // last range int prev = 0; // j is used as a counter for ranges for(int j = 0; j < ranges.Count; j++) { int start = ((Pair)ranges[j]).first; int end = ((Pair)ranges[j]).second; for(int i = prev + 1; i < start; i++) ans.Add(i); prev = end; } // For last segment for(int i = prev + 1; i <= m; i++) ans.Add(i); // Finally print all answer for(int i = 0; i < ans.Count; i++) { if ((int)ans[i] <= m) Console.Write(ans[i] + " "); }}// Driver codepublic static void Main(string[] args){ int M = 6; // Store ranges in vector of pair ArrayList ranges = new ArrayList(); ranges.Add(new Pair(1, 2)); ranges.Add(new Pair(4, 5)); findMissingNumber(ranges, M);}}// This code is contributed by rutvik_56 |
PHP
<?php// PHP program to find missing// elements from given Ranges// Function to find missing elements// from given Rangesfunction findMissingNumber($ranges, $m){ // First of all sort all the // given ranges sort($ranges); // store ans in a different vector $ans = []; // prev is use to store end // of last range $prev = 0; // j is used as a counter for ranges for ($j = 0; $j < count($ranges); $j++) { $start = $ranges[$j][0]; $end = $ranges[$j][1]; for ($i = $prev + 1; $i < $start; $i++) array_push($ans, $i); $prev = $end; } // for last segment for ($i = $prev + 1; $i < $m + 1; $i++) array_push($ans, $i); // finally print all answer for ($i = 0; $i < count($ans); $i++) { if ($ans[$i] <= $m) echo "$ans[$i] "; }}// Driver Code$N = 2;$M = 6;// Store ranges in vector of pair$ranges = [];array_push($ranges, [1, 2]);array_push($ranges, [4, 5]);findMissingNumber($ranges, $M)// This code is contributed// by Srathore?> |
Javascript
<script>// Javascript program to find missing elements// from given Ranges// Function to find missing elements// from given Rangesfunction findMissingNumber(ranges, m){ // First of all sort all the given ranges ranges.sort(); // store ans in a different vector let ans=[]; // prev is use to store end of // last range let prev = 0; // j is used as a counter for ranges for (let j = 0; j < ranges.length; j++) { let start = ranges[j][0]; let end = ranges[j][1]; for (let i = prev + 1; i < start; i++) ans.push(i); prev = end; } // for last segment for (let i = prev + 1; i <= m; i++) ans.push(i); // finally print all answer for (let i = 0; i < ans.length; i++) { if (ans[i] <= m) document.write(ans[i]," "); }}// Driver code let N = 2; let M = 6; // Store ranges in vector of pair let ranges=[]; ranges.push([ 1, 2 ]); ranges.push([ 4, 5 ]); findMissingNumber(ranges, M); // This code is contributed by Pushpesh Raj</script> |
Time Complexity: O(n * log(n)), where n is the length of the vector
Auxiliary Space: O(n)
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