67 lines
1.5 KiB
C++
67 lines
1.5 KiB
C++
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//majority element of an array
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// element with frequency > (n/2) {n: size of array}
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//time complexity : O(n) || space complexity : O(1)
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#include<iostream>
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using namespace std;
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void ismaj(int arr[],int n,int exp_maj){ // checks the if the candidate element is actually the majority element or not
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int i=0;
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int count =0;
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for(i=0;i<n;i++){
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if(arr[i]==arr[exp_maj]){
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count++;
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}
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}
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if(count>(n/2)){
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cout<<"majority element : "<<arr[exp_maj];
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}
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else{
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cout<<"no majority element found\n";
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}
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}
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int majelement(int arr[],int n){ // majority element function to find the candidate majority element
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int ans_index=0; // setting ans_index initially as the first element
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int count =1; // setting count of first element as 1
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for(int i=0;i<n;i++){
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if(arr[i]==arr[ans_index]){
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count++;
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}
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else{
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count--;
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}
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if(count ==0){
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ans_index=i; // updating ans_index as the ith element
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count =1; // resetting count
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}
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}
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return ans_index;// expected majority element
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}
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int main(){ // main function begins here
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int size;
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cout<<"enter the size of the array : ";
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cin>>size;
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int *arr = new int[size];
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for(int i=0;i<size;i++){
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cout<<"enter "<<i<<" th element of array : ";
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cin>>arr[i];
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}
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int result = majelement(arr,size);
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ismaj(arr,size,result);
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return 0;
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}
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