Restoring a Shuffled Queue in C++
This scenario presents an interesting problem: we have a queue of elements that's been shuffled, but each element holds an integer clue. This clue indicates the number of elements originally taller than it in the queue. Our goal is to utilize these clues to unscramble the queue and restore the original order.
Understanding the Problem
Imagine a line of people waiting in an unknown order. Luckily, each person has a note revealing how many taller people were originally in front of him or her. By cleverly using this information, we can determine the correct order for everyone in the line.
Data Structures
In order to handle the elements and their associated information, we'll utilize a std::vector in C++. This versatile container allows us to store pairs of values. Each pair will represent an element:
- The first element in the pair will be the actual element itself.
- The second element signifies the number of elements originally taller than it is in the queue.
Algorithm Overview:
We will employ a combination of data structures and sorting techniques to efficiently restore the shuffled queue. Here's an overview of the algorithm:
- First, convert the queue into a vector for easier manipulation.
- Identify the misplaced elements in the vector.
- Sort the misplaced elements based on a specific condition.
- Place the sorted elements back into the original queue, maintaining the order of the remaining elements.
Example:
Let's take an example to illustrate how to restore a shuffled queue in C++.
#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;
// Function to restore the shuffled queue
void restoreQueue(queue<int>& q) {
// Step 1: Convert the queue into a vector
vector<int> vec;
while (!q.empty()) {
vec.push_back(q.front());
q.pop();
}
// Step 2: Identify misplaced elements
vector<int> misplaced;
for (int i = 0; i < vec.size(); ++i) {
if (vec[i] != i + 1) { // Condition for misplacement
misplaced.push_back(vec[i]);
}
}
// Step 3: Sort the misplaced elements based on a condition
sort(misplaced.begin(), misplaced.end()); // Example: Sorting in ascending order
// Step 4: Place sorted elements back into the original queue
int idx = 0;
for (int i = 0; i < vec.size(); ++i) {
if (vec[i] == i + 1) { // If the element is in the correct position
q.push(vec[i]);
} else {
q.push(misplaced[idx++]);
}
}
}
int main() {
// Example usage
queue<int> q;
q.push(2);
q.push(1);
q.push(4);
q.push(3);
restoreQueue(q);
// Output the restored queue
while (!q.empty()) {
cout << q.front() << " ";
q.pop();
}
return 0;
}
Output:
![Restoring a Shuffled Queue in C++](https://static.tutorialandexample.com/cpp/restoring-a-shuffled-queue-in-cpp1.png)
s traversal, visited cells are marked to prevent re-exploration while the function also determines the size of the connected region being currently explored. In the end, each component's size is appended to the sizes vector after exploration..