diff --git "a/lkhyun/202509/28 BOJ G4 \354\242\213\353\213\244.md" "b/lkhyun/202509/28 BOJ G4 \354\242\213\353\213\244.md" new file mode 100644 index 00000000..6d384b89 --- /dev/null +++ "b/lkhyun/202509/28 BOJ G4 \354\242\213\353\213\244.md" @@ -0,0 +1,50 @@ +```java +import java.util.*; +import java.io.*; + +public class Main{ + static BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out)); + static StringTokenizer st; + static StringBuilder sb = new StringBuilder(); + static int N; + static int[] arr; + + public static void main(String[] args) throws Exception { + N = Integer.parseInt(br.readLine()); + arr = new int[N]; + + st = new StringTokenizer(br.readLine()); + for (int i = 0; i < N; i++) { + arr[i] = Integer.parseInt(st.nextToken()); + } + Arrays.sort(arr); + + int cnt = 0; + for (int i = 0; i < N; i++) { + int left = 0; + int right = N-1; + while(left < right){ + if(left == i){ + left++; + continue; + } + if(right == i){ + right--; + continue; + } + if(arr[i] < arr[left] + arr[right]){ + right--; + }else if(arr[i] > arr[left] + arr[right]){ + left++; + }else{ + cnt++; + break; + } + } + } + bw.write(cnt+""); + bw.close(); + } +} +```