Leetcode/src/main/java/com/fishercoder/solutions/_725.java at master · ernestp56/Leetcode · GitHub

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
package com.fishercoder.solutions;

import com.fishercoder.common.classes.ListNode;

public class _725 {
    public static class Solution1 {
        /**
         * My very original solution, but verbose.
         */
        public ListNode[] splitListToParts(ListNode head, int k) {
            int len = getLength(head);
            int aveSize = len / k;
            int extra = len % k;
            ListNode[] result = new ListNode[k];
            for (int i = 0; i < k; i++) {
                result[i] = head;
                int aveSizeTmp = aveSize;
                aveSizeTmp += extra-- > 0 ? 1 : 0;
                int aveSizeTmp2 = aveSizeTmp;
                while (aveSizeTmp-- > 0) {
                    head = head.next;
                }
                if (result[i] != null) {
                    ListNode tmp = result[i];
                    while (tmp.next != null && aveSizeTmp2-- > 1) {
                        tmp = tmp.next;
                    }
                    tmp.next = null;
                }
            }
            return result;
        }

        private int getLength(ListNode root) {
            int len = 0;
            ListNode tmp = root;
            while (tmp != null) {
                len++;
                tmp = tmp.next;
            }
            return len;
        }
    }

    public static class Solution2 {
        /**
         * More concise version
         */
        public ListNode[] splitListToParts(ListNode head, int k) {
            int len = getLength(head);
            int aveSize = len / k;
            int extra = len % k;
            ListNode[] result = new ListNode[k];
            ListNode prev = null;
            for (int i = 0; i < k; i++, extra--) {
                result[i] = head;
                for (int j = 0; j < aveSize + (extra > 0 ? 1 : 0); j++) {
                    prev = head;
                    head = head.next;
                }
                if (prev != null) {
                    prev.next = null;
                }
            }
            return result;
        }

        private int getLength(ListNode root) {
            int len = 0;
            ListNode tmp = root;
            while (tmp != null) {
                len++;
                tmp = tmp.next;
            }
            return len;
        }
    }

    public static class Solution3 {
        /**
         * My original solution on 9/29/2021.
         */
        public ListNode[] splitListToParts(ListNode head, int k) {
            ListNode[] ans = new ListNode[k];
            int size = 0;
            ListNode tmp = head;
            while (tmp != null) {
                tmp = tmp.next;
                size++;
            }
            int minSize = size / k;
            int remainder = size % k;
            int i = 0;
            if (head == null) {
                while (i < k) {
                    ans[i++] = null;
                }
            }
            while (i < k) {
                ListNode node = head;
                tmp = node;
                int len = minSize;
                if (remainder > 0) {
                    remainder--;
                    len++;
                }
                while (len-- > 1) {
                    tmp = tmp.next;
                }
                head = tmp.next;
                tmp.next = null;
                ans[i] = node;
                i++;
            }
            return ans;
        }
    }
}