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| 1 | +#include<climits> |
| 2 | +#include<vector> |
| 3 | +class PriorityQueue { |
| 4 | + vector<int> pq; |
| 5 | + |
| 6 | + public: |
| 7 | + PriorityQueue() { |
| 8 | + // Implement the constructor here |
| 9 | + } |
| 10 | + |
| 11 | + /**************** Implement all the public functions here ***************/ |
| 12 | + |
| 13 | + void insert(int element) { |
| 14 | + pq.push_back(element); |
| 15 | + int childindex=pq.size()-1; |
| 16 | + |
| 17 | + while(childindex>0){ |
| 18 | + int parentindex=(childindex-1)/2; |
| 19 | + if(pq[parentindex]<pq[childindex]){ |
| 20 | + int temp=pq[parentindex]; |
| 21 | + pq[parentindex]=pq[childindex]; |
| 22 | + pq[childindex]=temp; |
| 23 | + } |
| 24 | + else{ |
| 25 | + break; |
| 26 | + } |
| 27 | + childindex=parentindex; |
| 28 | + } |
| 29 | + } |
| 30 | + |
| 31 | + int getMax() { |
| 32 | + if(isEmpty()){ |
| 33 | + return INT_MIN; |
| 34 | + } |
| 35 | + return pq[0]; |
| 36 | + } |
| 37 | + |
| 38 | + int removeMax() { |
| 39 | + if(isEmpty()){ |
| 40 | + return INT_MIN; |
| 41 | + } |
| 42 | + int ans=pq[0]; |
| 43 | + pq[0]=pq[pq.size()-1]; |
| 44 | + pq.pop_back(); |
| 45 | + int parentindex=0; |
| 46 | + int lci=2*parentindex+1; |
| 47 | + int rci=2*parentindex+2; |
| 48 | + while(lci<pq.size()){ |
| 49 | + int maxIndex=parentindex; |
| 50 | + if(pq[maxIndex]<pq[lci]){ |
| 51 | + maxIndex=lci; |
| 52 | + } |
| 53 | + if(rci<pq.size()&&pq[maxIndex]<pq[rci]){ |
| 54 | + maxIndex=rci; |
| 55 | + } |
| 56 | + if(maxIndex==parentindex){ |
| 57 | + break; |
| 58 | + } |
| 59 | + int temp=pq[parentindex]; |
| 60 | + pq[parentindex]=pq[maxIndex]; |
| 61 | + pq[maxIndex]=temp; |
| 62 | + parentindex=maxIndex; |
| 63 | + lci=2*parentindex+1; |
| 64 | + rci=2*parentindex+2; |
| 65 | + } |
| 66 | + return ans; |
| 67 | + } |
| 68 | + |
| 69 | + int getSize() { |
| 70 | + if(isEmpty()){ |
| 71 | + return 0; |
| 72 | + } |
| 73 | + return pq.size(); |
| 74 | + } |
| 75 | + |
| 76 | + bool isEmpty() { |
| 77 | + return pq.size()==0; |
| 78 | + } |
| 79 | +}; |
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