minor bug fixes

Author: arorarahul

heaps/question1.c

@@ -53,15 +53,13 @@ void makeHeap(int arr[],int size){
 	for(int i=start;i>=0;i--){
 		maxHeapify(arr,i,size);
 	}
-
-	display(arr,size);
 }
 
 int main(){
 	int arr[] = {9,6,5,0,8,2,1,3};
 	int size = sizeof(arr)/sizeof(arr[0]);
 
 	makeHeap(arr,size);
-
+	display(arr,size);
 	return 0;
 }

heaps/question2.c

@@ -31,7 +31,7 @@ void maxHeapify(int arr[],int i, int size){
 			largest = right;	
 		}
 	}
-	if(largest <= heapSize && largest != i){
+	if(largest <= heapSize-1 && largest != i){
 		temp = arr[largest];
 		arr[largest] = arr[i];
 		arr[i] = temp;
@@ -61,7 +61,7 @@ int increaseKey(int arr[], int index, int value, int size){
 	arr[i] = value;
 
 	while(i>=1 && arr[(i-1)/2]<arr[i]){
-		temp = arr[i/2];
+		temp = arr[(i-1)/2];
 		arr[(i-1)/2] = arr[i];
 		arr[i]=temp;
 		i = (i-1)/2;
@@ -158,12 +158,12 @@ int main(){
 				}
 				heap[size-1] = INT_MIN;
 				result = increaseKey(heap,size-1,value,size);
-				if(output == -1){
+				if(result == -1){
 					printf("heap is already empty\n");
-				}else if(output == -2){
+				}else if(result == -2){
 					printf("value is lesser than current value at that index\n");
 				}else{
-					printf("updated value is ..%d\n", output);
+					printf("updated value is ..%d\n", result);
 				}		
 				display(heap,size);	
 				break;

heaps/question5.c

@@ -20,15 +20,15 @@ void swap(int *a, int *b){
 
 void minHeapify(int *arr,int i, int size){
 	int left = 2*i+1,right=2*i+2,smallest, heapSize = size;
-	if(left < heapSize-1 && arr[i] < arr[left]){
+	if(left <= heapSize-1 && arr[i] < arr[left]){
 		smallest = i;
 	}else{
 		smallest = left;
 	}
-	if(right < heapSize-1 && arr[right] < arr[smallest]){
+	if(right <= heapSize-1 && arr[right] < arr[smallest]){
 		smallest = right;
 	}
-	if(smallest < heapSize - 1 && smallest !=i){
+	if(smallest <= heapSize - 1 && smallest !=i){
 		swap(&arr[smallest],&arr[i]);
 		minHeapify(arr,smallest,size);
 	}

heaps/question6.c

@@ -35,4 +35,61 @@ Time complexity: O(k) + O((n-k)logk) //k for building the heap having k elements
 that many time minheapify will be called
 Space complexity: O(1) //min heap and max heap do not require additional data structure. Same array can
 be manipulated unless mentioned in the question
-*/
+*/
+//METHOD1 - naive so not doing
+//METHOD2 - sorting and simple method done in arrays
+//METHOD3
+#include <stdio.h>
+#include <stdlib.h>
+#define MAX 100
+
+void maxHeapify(int *arr,int i, int size){
+	int left = 2*i+1;
+	int right = 2*i+2;
+	int temp, largest;
+
+	if(left < size && arr[left]>arr[i]){
+		largest = left;
+	}else{
+		largest = i;
+	}
+	if(right < size && arr[right]>arr[largest]){
+		largest = right;
+	}
+	if(largest < size && largest != i){
+		temp  = arr[largest];
+		arr[largest] = arr[i];
+		arr[i] = temp;
+		maxHeapify(arr, largest, size);
+	}
+}
+
+void display(int arr[],int size){
+	for(int i=0; i<size;i++){
+		printf("%d\t", arr[i]);
+	}
+	printf("\n");
+}
+
+void makeMaxHeap(int *arr, int size){
+	int index = size/2 -1;
+	for(int i=index;i>=0;i--){
+		maxHeapify(arr,i,size);
+	}
+	display(arr,size);
+}
+
+int main(){
+	int arr[MAX], size;
+	printf("Enter the array size\n");
+	scanf("%d",&size);
+	for(int i=0; i<size;i++){
+		printf("enter the %d th element\n", i);
+		scanf("%d",&arr[i]);
+	}
+
+	makeMaxHeap(arr,size);	
+	return 0;
+}
+
+