first commit

2022-12-15 23:51:04 +07:00
commit 87d51fb251
292 changed files with 12623 additions and 0 deletions
@@ -0,0 +1,35 @@
+import java.util.*;
+public class Main {
+
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int t = sc.nextInt();
+        while (t-- > 0) {
+            Long n = sc.nextLong();
+            Long k = sc.nextLong();
+            HashMap<Long, Long> hm = new HashMap<>();
+            for (int i = 0; i < n; i++) {
+                Long x = sc.nextLong();
+                if (hm.get(x) == null)
+                    hm.put(x, (long) 1);
+                else
+                    hm.put(x, hm.get(x) + 1);
+            }
+            long ans = 0;
+            for (Map.Entry<Long, Long> set : hm.entrySet()) {
+                long x = set.getKey();
+                long y = set.getValue();
+                if (x < (k + 1) / 2) {
+                    if (hm.get(k - x) != null)
+                        ans += y * hm.get(k - x);
+                }
+            }
+            if (k % 2 == 0 && hm.get(k / 2) != null) {
+                long x = hm.get(k / 2);
+                ans += n * (n - 1) / 2;
+            }
+            System.out.println(ans);
+        }
+    }
+}