Counting Sort

algorithms/Sorting/Counting_sort/README.md

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+## Implementation of Counting sort algorithm
+### Complexity if max(O(n), O(max_value))
+'''
+Input:
+5
+9 4 6 21 3
+'''
+'''
+Output:
+3 4 6 9 21
+'''

algorithms/Sorting/Counting_sort/counting_sort.cpp

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+#include<iostream>
+#include<bits/stdc++.h>
+using namespace std;
+
+// Complexeity is O(n + max_val) in case of integer sorting
+void csort(int* a, int n){
+    unordered_map<int, int> hash;
+    int max_val = INT_MIN;
+    for(int i=0; i<n; i++){
+      hash[a[i]]++;
+      if(a[i]>max_val)max_val = a[i];
+    }
+    int j=0;
+    for(int i=0; i<=max_val; i++){
+        while(hash[i]--){
+            a[j]=i;
+            j++;
+        }
+    }
+}
+int main(){
+    int n;
+    int* a;
+    cin>>n;
+    a = new int[n];
+    for(int i=0; i<n; i++)
+    cin>>a[i];
+    csort(a, n);
+    for(int i=0; i<n; i++)cout<<a[i]<<' ';
+    return 0;
+}