CP_DSA/a1.cpp at main · parthiv360/CP_DSA · GitHub

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#include <iostream>
#include <limits.h>
using namespace std;

void InputArray(int arr[], int size)
{
    for (int i = 0; i < size; i++)
    {
        cin >> arr[i];
    }
}

void PrintArray(int arr[], int size)
{
    for (int i = 0; i < size; i++)
    {
        cout << arr[i] << " ";
    }
    cout << endl;
}

int FirstOccurance(int arr[], int size, int key)
{
    int start = 0;
    int end = size - 1;
    int ans = -1;

    while (start <= end)
    {
        int mid = start + (end - start) / 2;

        if (arr[mid] == key)
        {
            ans = mid;
            end = mid - 1;
        }

        else if (key > arr[mid])
        {
            start = mid + 1;
        }
        else
        {
            end = mid - 1;
        }
    }
    return ans;
}

int LastOccurance(int arr[], int size, int key)
{
    int start = 0;
    int end = size - 1;
    int ans = -1;

    while (start <= end)
    {
        int mid = start + (end - start) / 2;

        if (arr[mid] == key)
        {
            ans = mid;
            start = mid + 1;
        }

        else if (key > arr[mid])
        {
            start = mid + 1;
        }
        else
        {
            end = mid - 1;
        }
    }
    return ans;
}

int main()
{
    int arr[100];
    int n;
    cin >> n;

    InputArray(arr, n);
    PrintArray(arr, n);
    cout << FirstOccurance(arr, n, 3) << endl;
    cout << LastOccurance(arr, n, 3) << endl;

    return 0;
}