From eaf2ebd544b89b7793a9dc3fc9648667d8815461 Mon Sep 17 00:00:00 2001
From: mishraabhinn <49574460+mishraabhinn@users.noreply.github.com>
Date: Wed, 20 May 2020 00:26:59 +0530
Subject: [PATCH] SwapSort.cpp (#754)

* Create Swap Sort(Minimum)

* Update Swap Sort(Minimum)

* Update Swap Sort(Minimum)

* Rename Swap Sort(Minimum) to SwapSort.cpp

* Update SwapSort.cpp

* Update SwapSort.cpp

* Update SwapSort.cpp

* Rename SwapSort.cpp to swap_sort.cpp

Co-authored-by: Christian Clauss <cclauss@me.com>
---
 sorting/swap_sort.cpp | 66 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 sorting/swap_sort.cpp

diff --git a/sorting/swap_sort.cpp b/sorting/swap_sort.cpp
new file mode 100644
index 000000000..a4ab1e57b
--- /dev/null
+++ b/sorting/swap_sort.cpp
@@ -0,0 +1,66 @@
+// C++ program to find minimum number of swaps required to sort an array
+#include <algorithm>
+#include <iostream>
+#include <utility>
+#include <vector>
+
+// Function returns the minimum number of swaps
+// required to sort the array
+int minSwaps(int arr[], int n) {
+    // Create an array of pairs where first
+    // element is array element and second element
+    // is position of first element
+    std::pair<int, int> arrPos[n];
+    for (int i = 0; i < n; i++) {
+        arrPos[i].first = arr[i];
+        arrPos[i].second = i;
+    }
+
+    // Sort the array by array element values to
+    // get right position of every element as second
+    // element of pair.
+    std::sort(arrPos, arrPos + n);
+
+    // To keep track of visited elements. Initialize
+    // all elements as not visited or false.
+    std::vector<bool> vis(n, false);
+
+    // Initialize result
+    int ans = 0;
+
+    // Traverse array elements
+    for (int i = 0; i < n; i++) {
+        // already swapped and corrected or
+        // already present at correct pos
+        if (vis[i] || arrPos[i].second == i)
+            continue;
+
+        // find out the number of node in
+        // this cycle and add in ans
+        int cycle_size = 0;
+        int j = i;
+        while (!vis[j]) {
+            vis[j] = 1;
+
+            // move to next node
+            j = arrPos[j].second;
+            cycle_size++;
+        }
+
+        // Update answer by adding current cycle.
+        if (cycle_size > 0) {
+            ans += (cycle_size - 1);
+        }
+    }
+
+    // Return result
+    return ans;
+}
+
+// program to test
+int main() {
+    int arr[] = {6, 7, 8, 1, 2, 3, 9, 12};
+    int n = (sizeof(arr) / sizeof(int));
+    std::cout << minSwaps(arr, n);
+    return 0;
+}