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| 1 | +#include <vector> |
| 2 | + |
| 3 | +class PriorityQueue { |
| 4 | + vector<int> pq; |
| 5 | + |
| 6 | + public: |
| 7 | + bool isEmpty() { |
| 8 | + return pq.size() == 0; |
| 9 | + } |
| 10 | + |
| 11 | + int getSize() { |
| 12 | + return pq.size(); |
| 13 | + } |
| 14 | + |
| 15 | + int getMin() { |
| 16 | + if (isEmpty()) { |
| 17 | + return 0; |
| 18 | + } |
| 19 | + |
| 20 | + return pq[0]; |
| 21 | + } |
| 22 | + |
| 23 | + void insert(int element) { |
| 24 | + pq.push_back(element); |
| 25 | + |
| 26 | + int childIndex = pq.size() - 1; |
| 27 | + |
| 28 | + while (childIndex > 0) { |
| 29 | + int parentIndex = (childIndex - 1) / 2; |
| 30 | + |
| 31 | + if (pq[childIndex] < pq[parentIndex]) { |
| 32 | + int temp = pq[childIndex]; |
| 33 | + pq[childIndex] = pq[parentIndex]; |
| 34 | + pq[parentIndex] = temp; |
| 35 | + } else { |
| 36 | + break; |
| 37 | + } |
| 38 | + |
| 39 | + childIndex = parentIndex; |
| 40 | + } |
| 41 | + } |
| 42 | + |
| 43 | + int removeMin() { |
| 44 | + if(isEmpty()){ |
| 45 | + return 0; |
| 46 | + } |
| 47 | + int ans=pq[0]; |
| 48 | + pq[0]=pq[pq.size()-1]; |
| 49 | + pq.pop_back(); |
| 50 | + int parentindex=0; |
| 51 | + int lci=2*parentindex+1; |
| 52 | + int rci=2*parentindex+2; |
| 53 | + while(lci<pq.size()){ |
| 54 | + int minIndex=parentindex; |
| 55 | + if(pq[minIndex]>pq[lci]){ |
| 56 | + minIndex=lci; |
| 57 | + } |
| 58 | + if(rci<pq.size()&&pq[minIndex]>pq[rci]){ |
| 59 | + minIndex=rci; |
| 60 | + } |
| 61 | + if(minIndex==parentindex){ |
| 62 | + break; |
| 63 | + } |
| 64 | + int temp=pq[minIndex]; |
| 65 | + pq[minIndex]=pq[parentindex]; |
| 66 | + pq[parentindex]=temp; |
| 67 | + parentindex=minIndex; |
| 68 | + lci=2*parentindex+1; |
| 69 | + rci=2*parentindex+2; |
| 70 | + } |
| 71 | + return ans; |
| 72 | + } |
| 73 | +}; |
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