Sorting an array of 0,1,2

codes/sortArray012.cpp

@@ -0,0 +1,76 @@
+/*
+PROBLEM STATEMENT : 
+  Given an array A[] consisting 0s, 1s and 2s. The task is to write a function that sorts the given array. 
+  The functions should put all 0s first, then all 1s and all 2s in last.
+*/
+
+// C++ program to sort an array 
+// with 0, 1 and 2 in a single pass 
+#include <bits/stdc++.h> 
+using namespace std; 
+
+// Function to sort the input array, 
+// the array is assumed 
+// to have values in {0, 1, 2} 
+void sort012(int a[], int arr_size) 
+{ 
+    int lo = 0; 
+    int hi = arr_size - 1; 
+    int mid = 0; 
+
+    // Iterate till all the elements 
+    // are sorted 
+    while (mid <= hi) { 
+        switch (a[mid]) { 
+
+        // If the element is 0 
+        case 0: 
+            swap(a[lo++], a[mid++]); 
+            break; 
+
+        // If the element is 1 . 
+        case 1: 
+            mid++; 
+            break; 
+
+        // If the element is 2 
+        case 2: 
+            swap(a[mid], a[hi--]); 
+            break; 
+        } 
+    } 
+} 
+
+// Function to print array arr[] 
+void printArray(int arr[], int arr_size) 
+{ 
+    // Iterate and print every element 
+    for (int i = 0; i < arr_size; i++) 
+        cout << arr[i] << " ";
+        cout<<endl; 
+} 
+
+// Driver Code 
+int main() 
+{ 
+    int n;
+    cin>>n;
+    int arr[n];
+    for(int i=0;i<n;i++)
+    cin>>arr[i];
+    cout<<"Original Array : ";
+    printArray(arr,n);
+    sort012(arr, n); 
+    cout << "After Sorting, array becomes : ";
+    printArray(arr, n); 
+
+    return 0; 
+} 
+
+/*
+OUTPUT:
+5
+2 1 0 1 0
+Original Array : 2 1 0 1 0
+After Sorting, array becomes : 0 0 1 1 2
+*/