Counting Distinct Integers In An Array With Frequency Analysis
Counting distinct integers in an array: use a frequency array (fr) to keep track of occurrences. If a value is new, increment counter and set fr[a[i]] to 1. Update fr[a[i]] for each occurrence.
#include<iostream>
using namespace std;
const int Nmax=100005;
int n, fr[Nmax], a[Nmax];
int main(){
cin>>n;
int cnt=0;
for(int i=1;i<=n;i++){
cin>>a[i];
if(fr[a[i]]==0){
cnt++;
}
fr[a[i]]++;
}
cout<<cnt<<endl;
return 0;
}
// For calc the no. of distinct integers in an array.
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