From 0cf239a812cd8c1bad79070d98c0e0c69f2b7d42 Mon Sep 17 00:00:00 2001
From: Pooja Gupta <gpooja@iitk.ac.in>
Date: Tue, 5 Nov 2019 21:28:23 +0530
Subject: [PATCH] Created PigeonHole sorting algorithm

---
 .../PigeonHole sorting algorithm.cpp          | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Data Structure/PigeonHole sorting algorithm.cpp

diff --git a/Data Structure/PigeonHole sorting algorithm.cpp b/Data Structure/PigeonHole sorting algorithm.cpp
new file mode 100644
index 000000000..174f405b9
--- /dev/null
+++ b/Data Structure/PigeonHole sorting algorithm.cpp	
@@ -0,0 +1,45 @@
+#include <bits/stdc++.h> 
+using namespace std; 
+/* Sorts the array using pigeonhole algorithm */
+void pigeonholeSort(int arr[], int n) 
+{ 
+    // Find minimum and maximum values in arr[] 
+    int min = arr[0], max = arr[0]; 
+    for (int i = 1; i < n; i++) 
+    { 
+        if (arr[i] < min) 
+            min = arr[i]; 
+        if (arr[i] > max) 
+            max = arr[i]; 
+    } 
+    int range = max - min + 1; // Find range 
+    // Create an array of vectors. Size of array 
+    // range. Each vector represents a hole that 
+    // is going to contain matching elements. 
+    vector holes[range]; 
+    // Traverse through input array and put every 
+    // element in its respective hole 
+    for (int i = 0; i < n; i++) 
+        holes[arr[i]-min].push_back(arr[i]); 
+    // Traverse through all holes one by one. For 
+    // every hole, take its elements and put in 
+    // array. 
+    int index = 0;  // index in sorted array 
+    for (int i = 0; i < range; i++) 
+    { 
+       vector::iterator it; 
+       for (it = holes[i].begin(); it != holes[i].end(); ++it) 
+            arr[index++]  = *it; 
+    } 
+} 
+
+int main() 
+{ 
+    int arr[] = {9,2,3,8,1,6,9}; 
+    int n = sizeof(arr)/sizeof(arr[0]); 
+    pigeonholeSort(arr, n); 
+    printf("Sorted order is : "); 
+    for (int i = 0; i < n; i++) 
+        printf("%d ", arr[i]);
+    return 0; 
+}