Merge pull request larissalages#261 from mulirow/add-cycle-sort

Added cyclesort.cpp

Author: larissalages

classical_algorithms/c++/cyclesort.cpp

@@ -0,0 +1,72 @@
+#include <bits/stdc++.h>
+
+using namespace std; 
+
+// Cycle sort is an optimal sorting algorithm regarding the number of memory memWrite to sort.
+
+// Algorithm:
+void cycleSort(int array[], int n){ 
+    int memWrite = 0; 
+
+    for(int cycle = 0; cycle <= n - 2; cycle++){ 
+        int start = array[cycle]; 
+        int pos = cycle; 
+
+        for(int i = (cycle + 1); i < n; i++){
+            if (array[i] < start){
+                pos++; 
+            }
+        }
+
+        if (pos == cycle){
+            continue; 
+        }
+
+        while (start == array[pos]){
+            pos += 1; 
+        }
+
+        if (pos != cycle){ 
+            swap(start, array[pos]); 
+            memWrite++; 
+        } 
+
+        while(pos != cycle){ 
+            pos = cycle; 
+
+            for(int i = cycle + 1; i < n; i++){
+                if (array[i] < start){
+                    pos += 1; 
+                }
+            }
+
+            while(start == array[pos]){
+                pos += 1; 
+            }
+
+            if(start != array[pos]){ 
+                swap(start, array[pos]); 
+                memWrite++; 
+            } 
+        } 
+    } 
+} 
+
+// Test:
+int main(){ 
+    int array[] = {5, 1, 9, 2, 91, 23, 519, 43, 19, 3, 4, 3, 10}; 
+    int n = sizeof(array) / sizeof(array[0]); 
+    cout << "Elements before cycle sort:\n";
+    for (int i = 0; i < n; i++){
+        cout << array[i] << " ";
+    }
+    cout << "\n";
+
+    cycleSort(array, n); 
+
+    cout << "Elements after cycle sort:\n";
+    for (int i = 0; i < n; i++){
+        cout << array[i] << " ";
+    }
+    cout << "\n";
+}

readme.md

@@ -52,7 +52,7 @@ Code | Test
 [0/1 Knapsack Problem](https://github.com/ErR0rpj/code_problems/blob/master/classical_algorithms/c%2B%2B/01_knapsack_problem.cpp) | Missing tests
 [Kadane's Algorithm](https://github.com/ErR0rpj/code_problems/blob/master/classical_algorithms/c%2B%2B/Kadane_Algorithm.cpp) | Missing tests
 [Topological Sort](https://github.com/ErR0rpj/code_problems/blob/master/classical_algorithms/c%2B%2B/Topological_sort.cpp) | Missing Tests
-[Bucket Sort](https://github.com/larissalages/code_problems/blob/master/classical_algorithms/c%2B%2B/bucketsort.cpp) | Missing tests
+[Cycle Sort](https://github.com/larissalages/code_problems/blob/master/classical_algorithms/c%2B%2B/cyclesort.cpp) | Missing tests
 [Bogo Sort](https://github.com/larissalages/code_problems/blob/master/classical_algorithms/c%2B%2B/bogosort.cpp) | Missing tests
 
 # Codeforces