upd

qa/entrance-exams/contest/Main.java

@@ -0,0 +1,122 @@
+import java.util.Scanner;
+import java.util.Arrays;
+
+public class Main {
+  public static void main(String[] args) {
+    task5();
+  }
+
+  static void task5() {
+    Scanner sc = new Scanner(System.in);
+    long count = 0;
+
+    while (sc.hasNextLine()) {
+        String line = sc.nextLine();
+        int wordLen = 0;
+        char lastChar = 0;
+
+        for (int i = 0; i < line.length(); i++) {
+            char ch = line.charAt(i);
+
+            if (Character.isLetter(ch)) {
+                wordLen++;
+                lastChar = ch;
+            } else {
+                if (wordLen == 1 && (lastChar == 'a' || lastChar == 'A')) {
+                    count++;
+                }
+                wordLen = 0;
+            }
+        }
+
+        if (wordLen == 1 && (lastChar == 'a' || lastChar == 'A')) {
+            count++;
+        }
+    }
+
+    sc.close();
+    System.out.println(count);
+  }
+
+
+  static void task4() {
+    Scanner sc = new Scanner(System.in);
+    int n = sc.nextInt();
+    sc.nextLine();
+    String s = sc.nextLine();
+    sc.close();
+
+    int count = 0;
+
+    for (char ch : s.toCharArray()) {
+      if (ch == 'a') {
+        count++;
+      }
+    }
+
+    System.out.println(count);
+  }
+
+  static void task3() {
+    Scanner sc = new Scanner(System.in);
+    int n = sc.nextInt();
+    sc.nextLine();
+
+    int[] rows_sum = new int[n];
+    int[] columns_sum = new int[n];
+    Arrays.fill(columns_sum, 0);
+
+    int[][] mat = new int[n][n];
+    for (int i = 0; i < n; i++) {
+
+      int row_sum = 0;
+
+      String[] srow = sc.nextLine().split(" ");
+      int[] row = new int[n];
+      for (int j = 0; j < n; j++) {
+        row[j] = Integer.parseInt(srow[j]);
+        row_sum += row[j];
+        columns_sum[j] += row[j];
+      }
+
+      mat[i] = row;
+      rows_sum[i] = row_sum;
+    }
+
+    sc.close();
+
+    // for (int i = 0; i < n; i++) {
+    //   System.out.println(Arrays.toString(mat[i]));
+    // }
+
+    // System.out.println("rows sum: " + Arrays.toString(rows_sum));
+    // System.out.println("columns sum: " + Arrays.toString(columns_sum));
+
+    int interesting_pairs = 0;
+
+    for (int i = 0; i < n; i++) {
+      for (int j = 0; j < n; j++) {
+        if (Math.abs(rows_sum[i] - columns_sum[j]) <= mat[i][j]) {
+          interesting_pairs++;
+        }
+      }
+    }
+
+    System.out.println(interesting_pairs);
+  }
+
+  static void task2() {
+    Scanner sc = new Scanner(System.in);
+    long n = sc.nextInt();
+    sc.close();
+    System.out.println(n == 1 ? 1 : 4 * (n - 1));
+  }
+
+  static void task1() {
+    Scanner sc = new Scanner(System.in);
+    long n = sc.nextInt();
+    sc.close();
+    long s = ((100 + n) * (n - 99)) / 2;
+    System.out.println(s);
+  }
+}