-
Notifications
You must be signed in to change notification settings - Fork 13
/
Arrays_SortArrayOf0s1s2s_DutchNationalFlagAlgo.java
83 lines (67 loc) · 2.13 KB
/
Arrays_SortArrayOf0s1s2s_DutchNationalFlagAlgo.java
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
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
// https://practice.geeksforgeeks.org/problems/sort-an-array-of-0s-1s-and-2s/0
// https://www.youtube.com/watch?v=oaVa-9wmpns (BEST Video Explanation)
// https://leetcode.com/problems/sort-colors/
// https://www.geeksforgeeks.org/sort-array-0s-1s-2s-simple-counting/
// https://www.geeksforgeeks.org/segregate-0s-and-1s-in-an-array-by-traversing-array-once/
class Arrays_SortArrayOf0s1s2s_DutchNationalFlagAlgo {
private static void sortArrayOf0s1s2sByDutchNationalFlagAlgo(int[] values) {
int left = 0;
int mid = 0;
int right = values.length - 1;
while(mid <= right) {
switch (values[mid]) {
case 0: swap(values, left, mid);
left++; mid++;
break;
case 1: mid++;
break;
case 2: swap(values, mid, right);
right--;
break;
}
}
}
private static void swap(int[] values, int a, int b) {
int temp = values[a];
values[a] = values[b];
values[b] = temp;
}
private static void sortArrayOf0s1s2s(int[] values) {
StringBuilder sb0 = new StringBuilder();
StringBuilder sb1 = new StringBuilder();
StringBuilder sb2 = new StringBuilder();
for (int value : values) {
if(value == 0) sb0.append(0 + " ");
else if(value == 1) sb1.append(1 + " ");
else if(value == 2) sb2.append(2 + " ");
}
System.out.println(sb0.append(sb1).append(sb2));
sb0.setLength(0);
sb1.setLength(0);
sb2.setLength(0);
}
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int t = Integer.parseInt(br.readLine().trim());
while(t-- > 0) {
int n = Integer.parseInt(br.readLine().trim());
String[] input = br.readLine().trim().split("\\s+");
int[] values = new int[n];
for (int i = 0; i < n; i++) {
values[i] = Integer.parseInt(input[i]);
}
//sortArrayOf0s1s2s(values);
// using Dutch National Flag
sortArrayOf0s1s2sByDutchNationalFlagAlgo(values);
StringBuilder sb = new StringBuilder();
for (int value : values) {
sb.append(value + " ");
}
System.out.println(sb);
sb.setLength(0);
}
}
}