From f87c3a65487c9b21af5a7e522f18c59d69eaf1bd Mon Sep 17 00:00:00 2001
From: Aswin Sampath <aswinsampath1401@gmail.com>
Date: Sat, 6 Mar 2021 21:51:36 +0530
Subject: [PATCH 1/2] Counting Sort

---
 src/.vscode/c_cpp_properties.json |  21 +++++
 src/counting_sort_demo.cpp        | 135 ++++++++++++++++++++++++++++++
 2 files changed, 156 insertions(+)
 create mode 100644 src/.vscode/c_cpp_properties.json
 create mode 100644 src/counting_sort_demo.cpp

diff --git a/src/.vscode/c_cpp_properties.json b/src/.vscode/c_cpp_properties.json
new file mode 100644
index 00000000..2ffb82d0
--- /dev/null
+++ b/src/.vscode/c_cpp_properties.json
@@ -0,0 +1,21 @@
+{
+    "configurations": [
+        {
+            "name": "Win32",
+            "includePath": [
+                "${workspaceFolder}/**"
+            ],
+            "defines": [
+                "_DEBUG",
+                "UNICODE",
+                "_UNICODE"
+            ],
+            "windowsSdkVersion": "10.0.17763.0",
+            "cStandard": "c17",
+            "cppStandard": "c++17",
+            "intelliSenseMode": "${default}",
+            "compilerPath": "D:/MinGW/bin/g++.exe"
+        }
+    ],
+    "version": 4
+}
\ No newline at end of file
diff --git a/src/counting_sort_demo.cpp b/src/counting_sort_demo.cpp
new file mode 100644
index 00000000..508675c3
--- /dev/null
+++ b/src/counting_sort_demo.cpp
@@ -0,0 +1,135 @@
+/*
+Author : Aswin Sampath 
+Topic : Counting Sort
+
+                            Counting Sort
+    When to use?
+        Vizualise the array/vector elements 
+        Amount of space needed by the algorithm = Range of the vector
+        Range of vector = Max(vector)- Min(vector)
+        If Range is of the order 10^5 then we can use counting sort subjet to the compiler 
+
+    How to Implement 
+        Sort the numbers according to their frequency/ number of occurences
+        Place the element in their respective position according to the ranking 
+
+    Time Complexity : O(n)
+    Space COmplexity : O(Max(arr)-Min(arr));
+*/
+
+
+#include<iostream>
+#include<vector>
+using namespace std;
+
+void printVector(vector<int>v){
+    cout<<"\n Vector elements \n ";
+    for(int element:v){
+        cout<<element<<" ";
+    }
+    cout<<"\n";
+}
+
+int findMin(vector<int>arr){
+    int minele = arr[0];
+    for(int ele:arr){
+        if(ele<=minele)minele=ele;
+    }
+    return minele;
+}
+
+int findMax(vector<int>arr){
+    int maxele = arr[0];
+    for(int ele:arr){
+        if(ele>=maxele)maxele=ele;
+    }
+    return maxele;
+}
+
+
+int findRange(vector<int>arr){
+    int maxele = findMax(arr);
+    int minele = findMin(arr);
+    return maxele - minele;
+}
+
+vector<int>freq;
+vector<int>output;
+
+void countingSort(vector<int> &arr,int range){
+
+    // cout<<"Size of arr = "<<arr.size()<<"\n";
+    output.resize(arr.size());
+    freq.resize(range+1);
+    
+    // Find the frequency for each element in the array
+    for(int ele : arr){
+        freq[ele]++;
+    }
+    //printVector(freq);
+
+    // Find the ranking for each element by using prefix sum 
+    for(int i=1;i<freq.size();i++){
+        freq[i]+=freq[i-1];
+    }
+    //printVector(freq);
+    /* Ranking  table
+    number  rank
+    0   -   1
+    1   -   3
+    2   -   7
+    3   -   10
+    4   -   14
+    5   -   17
+    6   -   21
+    7   -   25
+    8   -   28
+    9   -   30
+
+    */
+
+    // Arrange the Elements according their rank
+    for(int i=0;i<arr.size();i++){
+        int num = arr[i]; //The number in the array
+        int rank = freq[num]; // The rank of the number
+        output[rank-1]= num; // Since indexing starts from and rank from 1 we need to adjust the difference
+        freq[num]--; // Decrease the freq count of the number once it has been written to output
+    }
+    //printVector(output);
+
+    // Rewrite the output to the original array
+    for(int i=0;i<arr.size();i++){
+        arr[i]=output[i];
+    }
+    output.resize(0); // Free the output array space
+    cout<<"\n";
+}
+
+int main(){
+    
+    // TODO : Sort the below array
+    vector<int>arr = {2,3,7,4,6,8,9,2,5,4,8,3,1,6,7,2,5,7,6,1,4,2,3,9,8,7,4,5,6,0};
+    
+    /* Frequency Table
+    ele     freq
+    0   -   1   
+    1   -   2
+    2   -   4
+    3   -   3
+    4   -   4
+    5   -   3
+    6   -   4
+    7   -   4
+    8   -   3
+    9   -   2
+    */
+
+    // Vector Range = max(arr)-min(arr) = 9 - 0 = 9 Hence we require of a 9 space in frequency array
+    int range = findRange(arr);
+    cout<<"Before Sorting \n";
+    printVector(arr);
+    countingSort(arr,range); // Sorting algorithm
+    cout<<"After Sorting \n";
+    printVector(arr);
+}
+

From 7d6ce0e4f055c43462fde1d0d2fa0622ec023300 Mon Sep 17 00:00:00 2001
From: Aswin Sampath <aswinsampath1401@gmail.com>
Date: Sat, 6 Mar 2021 21:54:49 +0530
Subject: [PATCH 2/2] =?UTF-8?q?=F0=9F=91=8D=20Counting=20sort=20demo?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/.vscode/c_cpp_properties.json | 21 ---------------------
 1 file changed, 21 deletions(-)
 delete mode 100644 src/.vscode/c_cpp_properties.json

diff --git a/src/.vscode/c_cpp_properties.json b/src/.vscode/c_cpp_properties.json
deleted file mode 100644
index 2ffb82d0..00000000
--- a/src/.vscode/c_cpp_properties.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-    "configurations": [
-        {
-            "name": "Win32",
-            "includePath": [
-                "${workspaceFolder}/**"
-            ],
-            "defines": [
-                "_DEBUG",
-                "UNICODE",
-                "_UNICODE"
-            ],
-            "windowsSdkVersion": "10.0.17763.0",
-            "cStandard": "c17",
-            "cppStandard": "c++17",
-            "intelliSenseMode": "${default}",
-            "compilerPath": "D:/MinGW/bin/g++.exe"
-        }
-    ],
-    "version": 4
-}
\ No newline at end of file