chore(C): add Heap-sort (#285)

algorithms/C/README.md

@@ -18,6 +18,7 @@
 - [Bubble Sort](sorting/bubble-sort.c)
 - [Merge Sort](sorting/merge-sort.c)
 - [Insertion Sort](sorting/insertion-sort.c)
+- [Heap Sort](sorting/heap-sort.c)
 
 ## Strings
 - [Count Words](strings/count-words.c)

algorithms/C/sorting/heap-sort.c

@@ -0,0 +1,72 @@
+// Heap Sort in C
+  
+#include<stdio.h>
+#include<conio.h>
+void main()
+{
+    int heap[10], no, i, j, c, root, temp;
+ 
+    printf("\n Enter no of elements :");
+    scanf("%d", &no);
+    printf("\n Enter the nos : ");
+    for (i = 0; i < no; i++)
+       scanf("%d", &heap[i]);
+    for (i = 1; i < no; i++)
+    {
+        c = i;
+        do
+        {
+            root = (c - 1) / 2;             
+            if (heap[root] < heap[c])   /* to create MAX heap array */
+            {
+                temp = heap[root];
+                heap[root] = heap[c];
+                heap[c] = temp;
+            }
+            c = root;
+        } while (c != 0);
+    }
+ 
+    printf("\n Heap array : ");
+    for (i = 0; i < no; i++)
+        printf("%d\t ", heap[i]);
+    for (j = no - 1; j >= 0; j--)
+    {
+        temp = heap[0];
+        heap[0] = heap[j];    /* swap max element with rightmost leaf element */
+        heap[j] = temp;
+        root = 0;
+        do 
+        {
+            c = 2 * root + 1;    /* left node of root element */
+            if ((heap[c] < heap[c + 1]) && c < j-1)
+                c++;
+            if (heap[root]<heap[c] && c<j)    /* again rearrange to max heap array */
+            {
+                temp = heap[root];
+                heap[root] = heap[c];
+                heap[c] = temp;
+            }
+            root = c;
+        } while (c < j);
+    } 
+    printf("\n The sorted array is : ");
+    for (i = 0; i < no; i++)
+       printf("\t %d", heap[i]);
+    printf("\n Time Complexity : \n Best case = Avg case = Worst case = O(n logn) \n");
+    getch();
+}
+
+  /* Test Case:-
+  Enter no of elements :5
+  Enter the nos:
+  10
+  23
+  2
+  1
+  90
+  
+  Heap array :   90    23   2   1   10
+  The sorted array is : 1   2   10  23   90
+  Time Complexity:
+  Best case = Avg case = Worst case = O(n logn) */