diff --git a/src/PowerManager.java b/src/PowerManager.java
index b3ba370..f4c7295 100644
--- a/src/PowerManager.java
+++ b/src/PowerManager.java
@@ -1,95 +1,148 @@
-import java.util.List;
-import java.util.Random;
-
-/**
- * 负责添加幂运算
- */
-public class PowerManager {
-  private static final Random RANDOM = new Random();
-  
-  // 普通幂运算
-  public String addPowerOperations(String expression, List<Integer> numPositions) {
-    if (numPositions.isEmpty()) return expression;
-    
-    String[] tokens = expression.split(" ");
-    int targetIndex = chooseTargetIndex(tokens, numPositions, null);
-    
-    if (targetIndex != -1) {
-      tokens[targetIndex] = applyPower(tokens[targetIndex], tokens, targetIndex);
-    }
-    
-    return String.join(" ", tokens);
-  }
-  
-  // 避免加在 trig 已占用的位置，同时避免加在运算符右边
-  public String addPowerOperationsAvoid(String expression, List<Integer> numPositions, List<Integer> trigPositions) {
-    if (numPositions.isEmpty()) return expression;
-    
-    String[] tokens = expression.split(" ");
-    int targetIndex = chooseTargetIndex(tokens, numPositions, trigPositions);
-    
-    if (targetIndex != -1) {
-      tokens[targetIndex] = applyPower(tokens[targetIndex], tokens, targetIndex);
-    }
-    
-    return String.join(" ", tokens);
-  }
-  
-  // 选择合适的位置加幂运算
-  private int chooseTargetIndex(String[] tokens, List<Integer> numPositions, List<Integer> avoidPositions) {
-    for (int tries = 0; tries < 20; tries++) {
-      int idx = numPositions.get(RANDOM.nextInt(numPositions.size()));
-      
-      if ((avoidPositions == null || !avoidPositions.contains(idx)) && canApplyPower(tokens, idx)) {
-        return idx;
-      }
-    }
-    return -1;
-  }
-  
-  // 检查该位置是否可以加幂运算
-  private boolean canApplyPower(String[] tokens, int index) {
-    if (!isNumber(tokens[index])) return false;
-    if (tokens[index].contains("^") || tokens[index].contains("√")) return false; // 避免重复幂运算
-    
-    // 不能加在运算符右边
-    if (index > 0) {
-      String prev = tokens[index - 1];
-      if (prev.equals("/") || prev.equals("*") || prev.equals("+") || prev.equals("-")) {
-        return false;
-      }
-    }
-    return true;
-  }
-  
-  // 应用平方或开方（根号放左括号左侧，平方放右括号右侧）
-  private String applyPower(String token, String[] tokens, int index) {
-    boolean useSqrt = RANDOM.nextBoolean();
-    
-    if (useSqrt) {
-      // 根号放在左括号左侧，如果前面是左括号，则放在括号左边
-      if (index > 0 && tokens[index - 1].equals(")")) {
-        return "√" + token; // 特殊情况，仍然放数字前
-      }
-      if (index > 0 && tokens[index - 1].equals("(")) {
-        return "√" + token;
-      }
-      return "√" + token;
-    } else {
-      // 平方放在右括号右侧，如果后面是右括号，则放在括号右边
-      if (index < tokens.length - 1 && tokens[index + 1].equals(")")) {
-        return token + "^2";
-      }
-      return token + "^2";
-    }
-  }
-  
-  private boolean isNumber(String token) {
-    try {
-      Integer.parseInt(token);
-      return true;
-    } catch (NumberFormatException e) {
-      return false;
-    }
-  }
-}
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Random;
+
+public class PowerManager {
+  private static final Random RANDOM = new Random();
+  
+  //添加一次幂运算,30%概率再加一次
+  public String addPowerOperations(String expression, List<Integer> numPositions,
+                                   List<Integer> trigPositions) {
+    if (numPositions.isEmpty()) {
+      return expression;
+    }
+    
+    String[] tokens = expression.split(" ");
+    
+    addOnePower(tokens, numPositions, trigPositions);
+    if (RANDOM.nextDouble() < 0.3) {
+      addOnePower(tokens, numPositions, trigPositions);
+    }
+    
+    return String.join(" ", tokens);
+  }
+  
+  // 添加一次幂运算，平方/根号各50%
+  private void addOnePower(String[] tokens, List<Integer> numPositions, List<Integer> trigPositions) {
+    if (RANDOM.nextBoolean()) {
+      tryAddSquare(tokens, numPositions, trigPositions);
+    } else {
+      tryAddSqrt(tokens, numPositions, trigPositions);
+    }
+  }
+  
+  // 添加平方
+  private void tryAddSquare(String[] tokens, List<Integer> numPositions,
+                            List<Integer> trigPositions) {
+    int target = chooseTargetIndex(tokens, numPositions, trigPositions, true);
+    if (target != -1) {
+      tokens[target] = tokens[target] + "^2";
+    }
+  }
+  
+  // 添加根号
+  private void tryAddSqrt(String[] tokens, List<Integer> numPositions,
+                          List<Integer> trigPositions) {
+    int target = chooseTargetIndex(tokens, numPositions, trigPositions, false);
+    if (target != -1) {
+      tokens[target] = "√" + tokens[target];
+    }
+  }
+  
+  // 选择可插入位置
+  private int chooseTargetIndex(String[] tokens, List<Integer> numPositions,
+                                List<Integer> trigPositions, boolean isSquare) {
+    List<Integer> candidates = new ArrayList<>();
+    for (int idx : numPositions) {
+      String token = tokens[idx];
+      
+      // 避免 trig 位置
+      if (trigPositions != null && trigPositions.contains(idx)) {
+        continue;
+      }
+      // 不能已有运算
+      if (token.contains("^") || token.contains("√")) {
+        continue;
+      }
+      // 括号匹配检查
+      if ((token.equals("(") || token.equals(")")) && !checkParenCanAdd(tokens, idx, isSquare)) {
+        continue;
+      }
+      
+      // 根号/平方合法性
+      if (isSquare) {
+        if (isNumber(token) || token.equals(")")) {
+          candidates.add(idx);
+        }
+      }
+      if (!isSquare) {
+        if (isNumber(token) || token.equals("(")) {
+          candidates.add(idx);
+        }
+      }
+    }
+    
+    if (candidates.isEmpty()) {
+      return -1;
+    }
+    return candidates.get(RANDOM.nextInt(candidates.size()));
+  }
+  
+  // 检查括号匹配另一侧是否可以加运算
+  private boolean checkParenCanAdd(String[] tokens, int index, boolean isSquare) {
+    int match = findMatchingParen(tokens, index);
+    if (match == -1) {
+      return false;
+    }
+    
+    // 检查匹配括号是否已加运算
+    if (tokens[match].contains("^") || tokens[match].contains("√")) {
+      return false;
+    }
+    
+    // 左括号只能加根号，右括号只能加平方
+    if (isSquare && tokens[index].equals("(")) {
+      return false;
+    }
+    return isSquare || !tokens[index].equals(")");
+  }
+  
+  // 找匹配括号
+  private int findMatchingParen(String[] tokens, int index) {
+    if (tokens[index].equals("(")) {
+      int depth = 0;
+      for (int i = index; i < tokens.length; i++) {
+        if (tokens[i].equals("(")) {
+          depth++;
+        } else if (tokens[i].equals(")")) {
+          depth--;
+          if (depth == 0) {
+            return i;
+          }
+        }
+      }
+    } else if (tokens[index].equals(")")) {
+      int depth = 0;
+      for (int i = index; i >= 0; i--) {
+        if (tokens[i].equals(")")) {
+          depth++;
+        } else if (tokens[i].equals("(")) {
+          depth--;
+          if (depth == 0) {
+            return i;
+          }
+        }
+      }
+    }
+    return -1;
+  }
+  
+  private boolean isNumber(String token) {
+    try {
+      Integer.parseInt(token);
+      return true;
+    } catch (NumberFormatException e) {
+      return false;
+    }
+  }
+}