Update JuniorProblem.java

src/JuniorProblem.java

@@ -2,22 +2,50 @@ import java.util.Random;
 
 public class JuniorProblem implements ProblemsGenerator {
   private static final Random RANDOM = new Random();
+  private static final String[] OPERATORS = {"+", "-", "*", "/"};
+  private static final String[] POW_OPERATORS = {"√", "^2"};
   
   @Override
   public String generate() {
-    int count = RANDOM.nextInt(5) + 1; // 1~5个数
+    String primaryExpr = generatePrimaryExpression();
+    return addPowerOperators(primaryExpr);
+  }
+  
+  private String generatePrimaryExpression() {
+    int count = RANDOM.nextInt(4) + 2;
     StringBuilder sb = new StringBuilder();
+    
     for (int i = 0; i < count; i++) {
-      int num = RANDOM.nextInt(20) + 1;
-      if (RANDOM.nextBoolean()) {
-        sb.append(num).append("^2");
-      } else {
-        sb.append("√").append(num);
-      }
+      sb.append(RANDOM.nextInt(100) + 1);
       if (i < count - 1) {
-        sb.append(" + ");
+        sb.append(" ").append(OPERATORS[RANDOM.nextInt(OPERATORS.length)]).append(" ");
       }
     }
     return sb.toString();
   }
+  
+  private String addPowerOperators(String expr) {
+    String[] parts = expr.split(" ");
+    boolean hasPower = false;
+    
+    for (int i = 0; i < parts.length; i++) {
+      if (parts[i].matches("\\d+") && (!hasPower || RANDOM.nextBoolean())) {
+        String op = POW_OPERATORS[RANDOM.nextInt(POW_OPERATORS.length)];
+        parts[i] = op.equals("√") ? "√" + parts[i] : parts[i] + "^2";
+        hasPower = true;
+      }
+    }
+    
+    if (!hasPower) {
+      for (int i = 0; i < parts.length; i++) {
+        if (parts[i].matches("\\d+")) {
+          String op = POW_OPERATORS[RANDOM.nextInt(POW_OPERATORS.length)];
+          parts[i] = op.equals("√") ? "√" + parts[i] : parts[i] + "^2";
+          break;
+        }
+      }
+    }
+    
+    return String.join(" ", parts);
+  }
 }