[INSTRUCTIONS]

You are a program-analysis assistant. Your task is to statically analyze the control dependence of a given code snippet. 

## 1. Control Dependence Definition
  Control dependence captures the influence of control-flow decisions on the execution of statements.

  A statement `S2` is control-dependent on `S1` if there is a **transitive** (indirect) chain of **direct** control dependencies from `S1` to `S2`. This is equivalent to saying that `S1` has control dependence over `S2`, meaning `S1`’s condition influences whether `S2` executes.


  **Direct Control Dependence**:
  A statement `S2` is **directly** control-dependent on a statement `S1` if:
  
  1.	`S1` is a conditional control statement (e.g., an `if`, `while`, `for`, `switch`, etc.).
  
  2.	`S1` directly determines whether `S2` executes. That is, `S1` has multiple successor branches, 

  - there exists **at least one branch** in which `S2` **always executes**, and
  - there exists **at least one other branch** in which `S2` does **not necessarily execute**.

    “Not necessarily execute” means that `S2` might execute or might not, but it is **not guaranteed** to execute in that branch.

  `S2` is **control-dependent** on `S1` if there exists a **transitive chain** of control dependencies from `S1` to `S2`, where each intermediate step in the chain represents a **direct** control dependence between two statements.



## 2. Output Format
When asked, "Which lines have control dependence over `targetLine`? List all such lines." You should respond in JSON format as follows:
```json
{
  "ControlDependenceSources": [S1, ..., S2]
}
```
  
If you believe there is no line that has control dependence over `targetLine`, respond:
```json
{
  "ControlDependenceSources": []
}
```


    

## 3. Interprocedural Control Dependence
  All dependence analysis is performed within **a single function**. We do not track dependencies across function boundaries. The analysis only applies to variables and control structures inside the **specified function**.


## 4. Example Code Snippet

### Example 1

```python
1  if x > 0:
2      y = 10       # this line is directly control-dependent on line 1 (x>0)
3      if y > 5:
4          z = 20   # this line is directly control-dependent on line 3 (y>5)
5          w = 30   # this line is directly control-dependent on line 3 (y>5)
6  v = 40           # this line is NOT control-dependent on any line
```


**Analysis**:
- Line 2 is directly control-dependent on line 1 (`x>0`)
- Lines 4 and 5 are directly control-dependent on line 3 (`y>5`).
- Lines 4 and 5 are **indirectly** control-dependent on line 1 (`x>0`) becasue even if line 1 (`x>0`) is `true`, lines 4 and 5 may not execute if line 3’s condition (`y>5`) is `false`. However, since control dependence is transitive, lines 4 and 5 are **indirectly** control-dependent on line 1. 
- Line 6 is not control-dependent on any lines because Line 6 always executes, regardless of whether line 1 (`x>0`) or line 3 (`y>5`) is true or false.



#### Example Question 1.1: 
Which lines have control dependence over line `5`? List all such lines.


**Output**: 
```json
{
  "ControlDependenceSources": [1, 3]
}
```

#### Example Question 1.2:
Which lines have control dependence over line `6`? List all such lines.

**Output**: 
```json
{
  "ControlDependenceSources": []
}
```


### Example 2

```python
1  count = 0
2  if count < 5:
3      count += 1
4  print("Step 1 done")
5  while count < 10:
6      if count == 7:
7          break
8      if count % 2 == 0:
9          continue
10     count += 2
11     if count > 9:
12         count = 9
13     print("Iteration done")
14 print("End of program")
```

#### Example Question 2.1: 
Which lines have control dependence over line `13`? List all such lines.

**Analysis**:
  - Line 13 is directly control-dependent on line 8 because if line 8 evaluates to `true`, continue skips line 13 for that iteration.
  - Line 8 is directly control-dependent on line 6 because if line 6 evaluates to `true`, the break statement terminates the loop, preventing line 8 from executing.
  - Line 6 is directly control-dependent on line 5 because the loop condition at line 5 determines whether line 6 executes. If line 5 evaluates to `false`, execution skips the loop entirely.


**Output**:
```json
{
  "ControlDependenceSources": [5, 6, 8]
}
```

#### Example Question 2.2: 
Which lines have control dependence over line `10`? List all such lines.


**Analysis**: Similar to the explanation above, line 8 is an `if` condition inside the `while` loop with a `continue`, so it can make the execution skip the rest of the loop entirely, including line 10. 



**Output**:
```json
{
  "ControlDependenceSources": [5, 6, 8]
}
```


#### Example Question 2.3: 
Which lines have control dependence over line `14`? List all such lines.

**Analysis**: Line 14 is outside the while loop (lines 5 -- 13) and will be executed regardless of the condition. 

**Output**:
```json
{
  "ControlDependenceSources": []
}
```


#### Example Question 2.4: 
Which lines have control dependence over line `12`? List all such lines.

**Analysis**: Line 2 doesn't affect whether line 12 is reached. The condition in line 2 only controls whether line 3 is executed. Line 12 is in while loop (line 5 -- 13) and will or will not be executed regardless of the condition in line 2. 

**Output**:
```json
{
  "ControlDependenceSources": [5, 6, 8, 11]
}
```

---

[YOUR TURN]

Below is **your target snippet**. 

```Python
1   def leastHacks(shieldStrength, robotsProgram):
2       shoot  = 'S'
3       charge = 'C'
4       totalDamage      = 0
5       currentDamage    = 1
6       hacksRequired    = 0
7       chargeIndexes    = []
8       chargeInfo       = {}
9       shotsAfterCharge = 0
10      firstCharge      = True
11      previousCharge   = 0
12      for index, action in enumerate(robotsProgram):
13          if action == charge:
14              if firstCharge:
15                  chargeInfo[index] = {'shotsAfter': shotsAfterCharge, 'damage': currentDamage, 'previousCharge': None}
16                  firstCharge = False
17              else:
18                  chargeInfo[previousCharge]['shotsAfter'] = shotsAfterCharge
19                  chargeInfo[index] = {'shotsAfter': 0, 'damage': currentDamage, 'previousShot': previousCharge}
20                  shotsAfterCharge = 0
21              previousCharge = index
22              chargeIndexes.append(index)
23              currentDamage *= 2
24          else:
25              if not firstCharge:
26                  shotsAfterCharge += 1
27              totalDamage += currentDamage
28      if not firstCharge:
29          chargeInfo[previousCharge]['shotsAfter'] = shotsAfterCharge
30      stackLength = len(chargeIndexes)
31      if totalDamage <= shieldStrength:
32          return hacksRequired
33      elif stackLength == 0:
34          return "IMPOSSIBLE"
35      for index, action in enumerate(robotsProgram[::-1]):
36          if action == shoot:
37              if stackLength == 0:
38                  return "IMPOSSIBLE"
39              closestCharge = chargeInfo[chargeIndexes.pop()]
40              stackLength -= 1
41              totalDamage -= closestCharge['shotsAfter'] * closestCharge['damage']
42              hacksRequired += closestCharge['shotsAfter']
43              if totalDamage <= shieldStrength:
44                  return hacksRequired
45              if not closestCharge['previousShot']:
46                  chargeInfo[closestCharge['previousShot']]['shotsAfter'] += closestCharge['shotsAfter']
47      return "IMPOSSIBLE"
48  def main():
49      T     = int(raw_input().strip())
50      cases = []
51      for _ in range(T):
52          temp = raw_input().strip().split(' ')
53          temp[0] = int(temp[0])
54          cases.append(temp)
55      print(T, cases)
56      for shieldStrength, robotsProgram in cases:
57          print(leastHacks(shieldStrength, robotsProgram))
58  if __name__ == "__main__":
59      main()
```


**Question**: Which lines have control dependence over line `27` in function `leastHacks`? List all such lines.

**Output**:


Ground truth answer: yes