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search.cpp
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search.cpp
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#include <iostream>
#include <vector>
using namespace std;
int linearSearchIterative(vector<int> arr, int element)
{
for (int i = 0; i < arr.size(); i++)
{
if (arr[i] == element)
return i;
}
return -1;
}
int linearSearchRecursive(vector<int> arr, int element, int index = 0)
{
if (index > arr.size())
return -1;
if (arr[index] == element)
return index;
return linearSearchRecursive(arr, element, ++index);
}
int binarySearchIterative(vector<int> arr, int element)
{
int low = 0, mid, high = arr.size() - 1;
while (low <= high)
{
mid = low + (high - low) / 2; // which is the same as (low + high) / 2
// The above expression was used to avoid signed integer overflow
if (arr[mid] == element)
return mid;
if (arr[mid] < element)
low = mid + 1;
else
high = mid - 1;
}
return -1;
}
int binarySearchRecursive(vector<int> arr, int low, int high, int element)
{
if (low <= high)
{
int mid = low + (high - low) / 2;
if (arr[mid] == element)
return mid;
if (arr[mid] < element)
return binarySearchRecursive(arr, mid + 1, high, element);
else
return binarySearchRecursive(arr, low, mid - 1, element);
}
return -1;
}
int sqrtUsingBinarySearch(int n)
{
int low = 0, high = n, mid, ans;
while (low <= high)
{
mid = (low + high) / 2;
if (mid * mid == n)
ans = mid;
if (mid * mid < n)
{
low = mid + 1;
ans = mid;
}
else
high = mid - 1;
}
return ans;
}