/
BOJ1253.java
56 lines (40 loc) · 1.23 KB
/
BOJ1253.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
import java.io.*;
import java.util.*;
public class Main {
public static int N;
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
N = Integer.parseInt(br.readLine());
String[] numberString = br.readLine().split(" ");
Integer[] numbers = Arrays.stream(numberString).map(Integer::new).toArray(Integer[]::new);
Arrays.sort(numbers);
int ans = 0;
for (int i = 0; i < N; ++i) {
int target = numbers[i];
int st = 0;
int en = N-1;
int val;
while (st != en) {
if (en == i) {
en--;
continue;
}
if (st == i) {
st++;
continue;
}
val = numbers[st] + numbers[en];
if (val == target) {
ans++;
break;
} else if (val < target) {
st++;
} else {
//val > target
en--;
}
}
}
System.out.println(ans);
}
}