Create counting_sort.cpp

dsa-roadmaps/Beginners/Algorithms/Sorting/counting_sort.cpp

@@ -0,0 +1,51 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
+#define endl "\n"
+#define int long long
+
+void countSort(int a[], int n) //O(n+k)
+{
+  int max = *max_element(a,a+n); //max=k
+  int count[max+1] = {0};
+
+  for(int i=0; i<n; i++)
+  {
+    count[a[i]]++;
+  }
+
+  for(int i=1; i<=max; i++)
+  {
+    count[i]+=count[i-1];
+  } 
+
+  int b[n]={0};
+
+  //start from end to maintain the stability of sorting
+  for(int i=n-1; i>=0; i--)
+  {
+    count[a[i]]--;
+    b[count[a[i]]] = a[i];
+  }
+
+  for(int i=0; i<n; i++)
+  {
+    cout<<b[i]<<" ";
+  }
+
+}
+
+int32_t main()
+{
+  IOS;
+  int n;
+  cin>>n;
+  int arr[n];
+  for(int i=0; i<n; i++)
+  {
+    cin>>arr[i];
+  }
+  countSort(arr, n);
+  return 0;
+}