Implementation of lower_bound() and upper_bound() on Map of Pairs in C++

Last Updated : 31 May, 2020

Prerequisite: map lower_bound() function in C++ STL, map upper_bound() function in C++ STL In this article, we will discuss the implementation of the lower_bound() and upper_bound() in the Map of pairs.

lower_bound(): It returns an iterator pointing to the first element in the range [first, last) which has a value greater than or equals to the given value "val". But in Map of Pairs lower_bound() for pair(x, y) will return an iterator pointing to the pair whose first value is greater than or equals x and second value is greater than equals to y. If the above-mentioned criteria are not met, then it returns an iterator which points to the pair {Map.size(), 0}. Syntax:
```
  mp.lower_bound({a, b})    where,  mp is the map of pairs  and {a, b} whose lower_bound  is to be found  
```
upper_bound(): It returns an iterator pointing to the first element in the range [first, last) which has a value greater than the given value "val". But in Map of Pairs upper_bound() for pair(x, y) will return an iterator pointing to the pair whose first value is greater than x and second value is greater than y. If the above-mentioned criteria are not met, then it returns an iterator which points to the pair {Map.size(), 0}. Syntax:
```
  mp.upper_bound({a, b})    where,  mp is the map of pairs  and {a, b} whose upper_bound  is to be found  
```

Below is the program to demonstrate lower_bound() and upper_bound() in Map of pairs: Program 1:

CPP

// C++ program to demonstrate lower_bound() // and upper_bound() in Map of Pairs  #include <bits/stdc++.h> using namespace std;  // Function to implement lower_bound() void findLowerBound(     map<pair<int, int>, int>& mp,     pair<int, int>& p) {      // This iterator points to the     // lower_bound() of given pair     auto low = mp.lower_bound(p);      cout << "lower_bound() for {2, 5}"          << " is: {"          << (*low).first.first << ", "          << (*low).first.second          << "}" << endl; }  // Function to implement upper_bound() void findUpperBound(     map<pair<int, int>, int>& mp,     pair<int, int>& p) {      // This iterator points to the     // upper_bound() of given pair     auto up = mp.upper_bound(p);      cout << "upper_bound() for {2, 5}"          << " is: {"          << (*up).first.first << ", "          << (*up).first.second          << "}" << endl; }  // Driver Code int main() {     // Declare map of Pairs     map<pair<int, int>, int> mp;      // Insert Pairs in Map     mp.insert({ { 2, 3 }, 8 });     mp.insert({ { 4, 1 }, 5 });     mp.insert({ { 7, 1 }, 3 });     mp.insert({ { 9, 3 }, 1 });     mp.insert({ { 5, 0 }, 3 });      // Given pair {2, 5}     pair<int, int> p = { 2, 5 };      // Function Call to find lower_bound     // of pair p in map mp     findLowerBound(mp, p);      // Function Call to find upper_bound     // of pair p in map mp     findUpperBound(mp, p);      return 0; }

Output:

  lower_bound() for {2, 5} is: {4, 1}  upper_bound() for {2, 5} is: {4, 1}

How to Convert a Map of Set of Pairs in C++?

dreamer07

Improve

Article Tags :

Practice Tags :

In this article we will discuss the implementation of the lower_bound() and upper_bound() in an array of pairs. lower_bound(): It returns an iterator pointing to the first element in the range [first, last) which has a value greater than or equals to the given value â€œvalâ€. But in Array of Pairs lowe

3 min read

Implementing upper_bound() and lower_bound() for Ordered Set in C++

Prerequisites: Ordered Set and GNU C++ PBDS Given an ordered set set and a key K, the task is to find the upper bound and lower bound of the element K in the set in C++. If the element is not present or either of the bounds could not be calculated, then print -1. Ordered set is a policy based data s

3 min read

How to Convert a Map of Set of Pairs in C++?

In C++, a map can be converted to a set of pairs. This can be useful when you want to create a set of pairs from a map, where each pair contains a key and a value. In this article, we will learn how to convert a map to a set of pairs in C++. Example Input: myMap = {{1, â€œoneâ€}, {2, â€œtwoâ€}, {3, â€œthree

2 min read

How to Add Elements to a Map in C++?

In C++, a map is an associative container that stores the elements as key-value pairs where each element has a key and a mapped value. In this article, we will learn how to add elements to a map in C++ STL. For Example, Input: myMap = {{1, "Ram"}, {2, "Mohit"}}; Output: myMap = {{1, "Ram"}, {2, "Moh

2 min read

How to Access Elements of Set of Maps in C++?

In C++, a set of maps can be used to store multiple maps of key-value pairs sorted according to their number and values of elements such as graphs. In this article, we will explore how we can access the elements of a set of maps in C++. Example: Input: { { {1: "C++"}, {2:" Python"} }, { {3:" Java"},

2 min read

How to Insert Elements from Vectors to a Map in C++?

In C++, vectors are the dynamic array that stores data in contiguous memory locations while maps are the data containers that store the key-value pair and are sorted on the basis of the key. In this article, we will learn how to efficiently map elements from vectors to a map in C++. Example Input: v

2 min read

How to Sort a Vector of Pairs Based on the Second Element of the Pair in C++?

In C++, a vector of pairs is a common data structure used to store pairs of values. Sometimes, when dealing with pairs we need to sort such vectors of pairs based on a specific element of the pair like sorting it based on the second element of each pair. In this article, we will learn how to sort a

3 min read

Difference between pair in Multiset and Multimap in C++ STL

Pairs in C++: The pair container is a simple container defined in <utility> header consisting of two data elements or objects. The first element is referenced as â€˜firstâ€™ and the second element as â€˜secondâ€™ and the order is fixed (first, second). Pair is used to combine together two values which

5 min read

How to Find the Minimum and Maximum Element of a Vector Using STL in C++?

In this article, we will learn how to find the minimum and maximum element in vector in C++. The simplest method to find the minimum and maximum element in vector is by using min_element() and max_element(). Letâ€™s take a look at a simple example: [GFGTABS] C++ #include <bits/stdc++.h> using na

2 min read

How to Implement Custom Hash Functions for User-Defined Types in std::unordered_map?

In C++ std::unordered_map is a data structure that implements a hash table and allows fast access to each element based on its key. However, when we want to use user-defined types as keys, we need to provide a custom hash function. In this article, we will learn how to implement a custom hash functi

3 min read

Implementation of lower_bound() and upper_bound() on Map of Pairs in C++

Similar Reads