Code : Remove Min

 

Implement the function RemoveMin for the min priority queue class.

For a minimum priority queue, write the function for removing the minimum element present. Remove and return the minimum element.

Note : main function is given for your reference which we are using internally to test the cod


#include <vector>
class PriorityQueue {
vector<int> pq;
public :
PriorityQueue() {
}
bool isEmpty() {
return pq.size() == 0;
}
// Return the size of priorityQueue - no of elements present
int getSize() {
return pq.size();
}
int getMin() {
if(isEmpty()) {
return 0; // Priority Queue is empty
}
return pq[0];
}
void insert(int element) {
pq.push_back(element);
int childIndex = pq.size() - 1;
while(childIndex > 0) {
int parentIndex = (childIndex - 1) / 2;
if(pq[childIndex] < pq[parentIndex]) {
int temp = pq[childIndex];
pq[childIndex] = pq[parentIndex];
pq[parentIndex] = temp;
}
else {
break;
}
childIndex = parentIndex;
}
}
int removeMin() {
if(isEmpty()){
return 0; // Priority Queue is Empty
}
int ans=pq[0];
pq[0]=pq[pq.size()-1];
pq.pop_back();
// down-heapify
int parentIndex=0;
int leftChildIndex=2*parentIndex+1;
int rightChildIndex=2*parentIndex+2;
while(leftChildIndex<pq.size()){
int minIndex=parentIndex;
if(pq[leftChildIndex]<pq[minIndex]){
minIndex=leftChildIndex;
}
if(rightChildIndex<pq.size() && pq[rightChildIndex]<pq[minIndex] ){
minIndex=rightChildIndex;
}
if(minIndex==parentIndex){
break;
}
int temp=pq[minIndex];
pq[minIndex]=pq[parentIndex];
pq[parentIndex]=temp;

parentIndex=minIndex;
leftChildIndex=2*parentIndex+1;
rightChildIndex=2*parentIndex+2;
}
return ans;
}
};







Comments

Post a Comment

Popular posts from this blog

Code : All connected components

  Given an undirected graph G(V,E), find and print all the connected components of the given graph G. Note: 1. V is the number of vertices present in graph G and vertices are numbered from 0 to V-1. 2. E is the number of edges present in graph G. 3. You need to take input in main and create a function which should return all the connected components. And then print them in the main, not inside function. Print different components in new line. And each component should be printed in increasing order (separated by space). Order of different components doesn't matter. Input Format : The first line of input contains two integers, that denote the value of V and E. Each of the following E lines contains two space separated integers, that denote that there exists an edge between vertex a and b. Output Format : Print different components in new line. And each component should be printed in increasing order of vertices (separated by space). Order of different components doesn't matter....
Read more

Coding Ninjas

  Given a NxM matrix containing Uppercase English Alphabets only. Your task is to tell if there is a path in the given matrix which makes the sentence “CODINGNINJA” . There is a path from any cell to all its neighbouring cells. For a particular cell, neighbouring cells are those cells that share an edge or a corner with the cell. Input Format : The first line of input contains two space separated integers N and M, where N is number of rows and M is the number of columns in the matrix. Each of the following N lines contain M characters. Please note that characters are not space separated. Output Format : Print 1 if there is a path which makes the sentence “CODINGNINJA” else print 0. Constraints : 1 <= N <= 1000 1 <= M <= 1000 Time Limit: 1 second Sample Input 1: 2 11 CXDXNXNXNXA XOXIXGXIXJX Sample Output 1: 1 bool hasPath ( vector < vector < char >> & board , int n , int m ) { // Write your code here. } #include < iostream > #include ...
Read more