-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathMerge-K-sorted-Arrays.java
More file actions
157 lines (127 loc) · 2.63 KB
/
Merge-K-sorted-Arrays.java
File metadata and controls
157 lines (127 loc) · 2.63 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
class Node {
int element;
int i;
int j;
public Node(int element, int i, int j) {
this.element = element;
this.i = i;
this.j = j;
}
}
class MinHeap {
int capacity;
Node arr[];
int size;
public MinHeap(Node[] arr) {
this.capacity = arr.length;
this.size = this.capacity;
this.arr = arr;
buildMinHeap();
}
void swap(Node[] arr, int i, int j) {
Node temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
int parent(int i) {
return (i-1)/2;
}
int left(int i) {
return 2*i + 1;
}
int right(int i) {
return 2*i + 2;
}
Node getMin() {
if(size <= 0) {
System.out.println("Heap underflow");
return null;
}
return arr[0];
}
Node extractMin() {
if(size <= 0) {
System.out.println("Heap underflow");
return null;
}
if(size == 1) {
size--;
return arr[0];
}
Node root = arr[0];
arr[0] = arr[size-1];
size--;
minHeapify(0);
return root;
}
void minHeapify(int i) {
int l = left(i);
int r = right(i);
int smallest = i;
if(l < size && arr[l].element < arr[smallest].element)
smallest = l;
if(r < size && arr[r].element < arr[smallest].element)
smallest = r;
if(smallest != i) {
swap(arr,i,smallest);
minHeapify(smallest);
}
}
void buildMinHeap() {
int n = arr.length;
for(int i = (n/2)-1;i>=0;i--)
minHeapify(i);
}
void replaceMin(Node root) {
arr[0] = root;
minHeapify(0);
}
void printMinHeap() {
for(int i=0;i<size;i++)
System.out.print(arr[i].element + " ");
System.out.println();
}
}
class MergeKSortedArrays {
static void mergeKSortedArrays(int[][] arr, int k) {
Node[] hArr = new Node[k];
int resultSize = 0;
for(int i=0;i<arr.length;i++) {
Node node = new Node(arr[i][0],i,1);
hArr[i] = node;
resultSize += arr[i].length;
}
MinHeap mh = new MinHeap(hArr);
int[] result = new int[resultSize];
for(int i=0;i<resultSize;i++) {
Node root = mh.getMin();
result[i] = root.element;
if(root.j < arr[root.i].length)
root.element = arr[root.i][root.j++];
else
root.element = Integer.MAX_VALUE;
mh.replaceMin(root);
}
printArray(result);
}
static void printArray2D(int[][] arr) {
for(int[] a : arr) {
for(int i : a)
System.out.print(i + " ");
System.out.println();
}
}
static void printArray(int[] arr) {
for(int i : arr)
System.out.print(i + " ");
System.out.println();
}
public static void main(String[] args) {
int[][] arr= {{2, 6, 8, 12, 34},
{1, 9, 20, 25, 100, 1000},
{23, 34, 90, 2000}};
System.out.println("Arrays:");
printArray2D(arr);
mergeKSortedArrays(arr,arr.length);
}
}