tim_sort.cpp

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
const int RUN = 32;
// This function sorts array from left
// index to to right index which is
// of size atmost RUN
void insertionSort(int arr[], int left, int right)
{
    for (int i = left + 1; i <= right; i++)
    {
        int temp = arr[i];
        int j = i - 1;
        while (j >= left && arr[j] > temp)
        {
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = temp;
    }
}
// Merge function merges the sorted runs
void merge(int arr[], int l, int m, int r)
{
    // Original array is broken in two
    // parts left and right array
    int len1 = m - l + 1, len2 = r - m;
    int left[len1], right[len2];
    for (int i = 0; i < len1; i++)
        left[i] = arr[l + i];
    for (int i = 0; i < len2; i++)
        right[i] = arr[m + 1 + i];
    int i = 0;
    int j = 0;
    int k = l;
    // After comparing, we
    // merge those two array
    // in larger sub array
    while (i < len1 && j < len2)
    {
        if (left[i] <= right[j])
        {
            arr[k] = left[i];
            i++;
        }
        else
        {
            arr[k] = right[j];
            j++;
        }
        k++;
    }
    // Copy remaining elements of
    // left, if any
    while (i < len1)
    {
        arr[k] = left[i];
        k++;
        i++;
    }
    // Copy remaining element of
    // right, if any
    while (j < len2)
    {
        arr[k] = right[j];
        k++;
        j++;
    }
}
// Iterative Timsort function to sort the
// array[0...n-1] (similar to merge sort)
void timSort(int arr[], int n)
{
    // Sort individual subarrays of size RUN
    for (int i = 0; i < n; i += RUN)
        insertionSort(arr, i, min((i + RUN - 1), (n - 1)));
    // Start merging from size RUN (or 32).
    // It will merge
    // to form size 64, then 128, 256
    // and so on ....
    for (int size = RUN; size < n; size = 2 * size)
    {
        // pick starting point of
        // left sub array. We
        // are going to merge
        // arr[left..left+size-1]
        // and arr[left+size, left+2*size-1]
        // After every merge, we
        // increase left by 2*size
        for (int left = 0; left < n; left += 2 * size)
        {
            // Find ending point of
            // left sub array
            // mid+1 is starting point
            // of right sub array
            int mid = left + size - 1;
            int right = min((left + 2 * size - 1), (n - 1));

            // merge sub array arr[left.....mid] &
            // arr[mid+1....right]
            if (mid < right)
                merge(arr, left, mid, right);
        }
    }
}
// Utility function to print the Array
void printArray(int arr[], int n)
{
    for (int i = 0; i < n; i++)
        printf("%d  ", arr[i]);
    printf("\n");
}
int main()
{
    // Taking size of array as input
    int n;
    cout << "ENTER THE SIZE OF ARRAY: : ";
    cin >> n;
    // Taking elements of array as input
    int arr[n];
    cout << "ENTER THE ELEMENTS: " << endl;
    for (int i = 0; i < n; i++)
    {
        cin >> arr[i];
    }
    // Printing unsorted array
    for (int i = 0; i < n; i++)
    {
        cout << arr[i] << " ";
    }
    cout << "\n";
    timSort(arr, n);
    cout << "After tim sort Array is " << endl;
    for (int i = 0; i < n; i++)
    {
        cout << arr[i] << " ";
    }
}