Sorting Algorithms

Data-Structures-And-Algorithms-Hacktoberfest18-master/Bubble_Sort.cpp

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+// Bubble Sort == Reapetedly swap two adjacent elements if they are in wrong order
+// For n elements in array == (n-1) iterations to get sorted array
+// If ith iteration == Check upto (n-i)
+#include<iostream>
+using namespace std;
+
+int main()
+{
+    int n;
+    cin >> n;
+
+    int arr[n];
+
+
+    for(int i=0;i<n;i++)
+    {
+        cin >> arr[i];
+    }
+
+    int counter = 1;
+    while(counter < n-1)
+    {
+        for(int i=0;i<n-counter;i++)
+        {
+            if(arr[i]>arr[i+1])
+            {
+                // Swapping the numbers
+                int temp = arr[i];
+                arr[i] = arr[i+1];
+                arr[i+1] = temp;
+            }
+        }
+        counter++;
+    }
+
+    for(int i=0;i<n;i++)
+    {
+        cout << arr[i] << " ";
+    }
+
+
+
+
+
+    return 0;
+}
+

Data-Structures-And-Algorithms-Hacktoberfest18-master/Count_Sort.cpp

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+// Name: JHALA DEVRAJSINH SHRIPALSINH
+// Date: 01/07/2021
+// Purpose: Count Sort time complexity better than Quick Sort and Merge Sort
+// Approach:
+// 1. Find the count of every distinct element in the array
+// 2. Calculate the position of each element in the sorted array
+
+// Time Complexity:
+// max(Ai,N) Ai = Creating array of appropriate range && Iterate the frequency array
+// N = Filling frequencies of each element
+
+#include<bits/stdc++.h>
+using namespace std;
+
+void countSort(int arr[], int n)
+{
+
+    int k = arr[0];
+    for(int i=0;i<n;i++)
+    {
+        k = max(k,arr[i]);
+    }
+
+    int count[10] = {0};
+    for(int i=0;i<n;i++)
+    {
+        count[arr[i]]++;
+    }
+
+    for(int i=1; i<=k;i++)
+    {
+        count[i] += count[i-1];
+    }
+
+    int output[n];
+    for(int i=n-1; i>=0;i++)
+    {
+        output[--count[arr[i]]] = arr[i];
+    }
+
+    for(int i=0;i<n;i++)
+    {
+        arr[i] = output[i];
+    }
+
+}
+
+
+int main()
+{
+
+    int arr[] = {1,3,2,3,4,1,6,4,3};
+    countSort(arr,9);
+    for(int i=0;i<9;i++)
+    {
+        cout << arr[i] << " ";
+    }
+
+    return 0;
+
+}

Data-Structures-And-Algorithms-Hacktoberfest18-master/DNF_Sort.cpp

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+// Name: JHALA DEVRAJSINH SHRIPALSINH
+// Date: 01/07/2021
+// Purpose: Dutch National Flag (DNF) Sort
+// Approach:
+// Check the value of arr[mid]:
+// if 0, swap arr[low] and arr[mid], low++, mid++
+// if 1, mid++
+// if 2, swap arr[mid] and arr[high], high--
+
+// Time complexity:
+// O(N) because in each operation, either mid gets incremented or high gets decremented
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+void swap(int arr[], int i, int j)
+{
+    int temp = arr[i];
+    arr[i] = arr[j];
+    arr[j] = temp;
+}
+
+
+void DNF_Sort(int arr[], int n)
+{
+    int low = 0;
+    int mid = 0;
+    int high = n - 1;
+
+    while(mid <= high)
+    {
+        if(arr[mid] == 0)
+        {
+            swap(arr,low,mid);
+            low++; mid++;
+        }
+
+        else if(arr[mid] == 1)
+        {
+            mid++;
+        }
+
+        else
+        {
+            swap(arr,mid,high);
+            high--;
+        }
+    }
+}
+
+
+
+int main()
+{
+
+    int arr[] = {1,0,2,1,0,1,2,1,2};
+    DNF_Sort(arr,9);
+
+    for(int i=0;i<9;i++)
+    {
+        cout << arr[i] << " ";
+    }
+
+    return 0;
+}

Data-Structures-And-Algorithms-Hacktoberfest18-master/Wave_Sort.cpp

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+// Name: JHALA DEVRAJSINH SHRIPALSINH
+// Date: 01/07/2021
+// Purpose: Wave Sort
+// Wave form like arr[0]>= arr[1] <= arr[2] >= arr[3] <= arr[4] >= ...
+
+// Time Complexity:
+// O(N/2) === O(N)
+// Final time complexity === O(N)
+
+#include<bits/stdc++.h>
+using namespace std;
+
+void swap(int arr[], int i, int j)
+{
+    int temp = arr[i];
+    arr[i] = arr[j];
+    arr[j] = temp;
+}
+
+void wavesort(int arr[], int n)
+{
+    for(int i=1; i<n; i+=2)
+    {
+        if(arr[i] > arr[i-1])
+        {
+            swap(arr,i,i-1);
+        }
+
+        if(arr[i] > arr[i+1] && i <= n-2)
+        {
+            swap(arr, i,i+1);
+        }
+    }
+}
+
+
+
+int main()
+{
+
+    int arr[] = {1,3,4,7,5,6,2};
+    wavesort(arr,7);
+
+    for(int i=0;i<7;i++)
+    {
+        cout << arr[i] << " ";
+    }
+
+    return 0;
+}