[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 get_next_location (num_of_people) :
2       coordinates_list = []
3       people_count = 1
4       while people_count <= num_of_people :
5           curr_location = raw_input("")
6           curr_location = curr_location.split()
7           x = int(curr_location[0])
8           y = int(curr_location[1])
9           dir = curr_location[2]
10          if (dir == "N") :
11              y += 1
12          if (dir == "S") :
13              y -= 1
14          if (dir == "E") :
15              x += 1
16          if (dir == "W") :
17              x -= 1
18          coordinates = []
19          coordinates.append(x)
20          coordinates.append(y)
21          coordinates_list.append(coordinates)
22          people_count += 1
23      next_dest = []
24      next_dest_count = []
25      for coordinates in coordinates_list :
26          found = 0
27          dest_idx = 0
28          for dest in next_dest :
29              if (coordinates == dest) :
30                  next_dest_count[dest_idx] += 1
31                  found = 1
32                  break
33              dest_idx += 1
34          if (found == 0) :
35              next_dest.append(coordinates)
36              next_dest_count.append(1)
37      popular_next_dest = []
38      popular_next_dest.append(next_dest[0])
39      highest_count = next_dest_count[0]
40      dest_count_idx = 0
41      for dest_count in next_dest_count :
42          if (dest_count_idx == 0) :
43              dest_count_idx += 1
44              continue
45          if (dest_count == highest_count) :
46              popular_next_dest.append(next_dest[dest_count_idx])
47          if (dest_count > highest_count) :
48              popular_next_dest = []
49              highest_count = dest_count
50              popular_next_dest.append(next_dest[dest_count_idx])
51          dest_count_idx += 1
52      if (len(popular_next_dest) == 1) :
53          return popular_next_dest[0]
54      else :
55          smallest_number = popular_next_dest[0]
56          dest_idx = 0
57          for dest in popular_next_dest :
58              if (dest_idx == 0) :
59                  dest_idx += 1
60                  continue
61              if (dest < smallest_number) :
62                  smallest_number = dest
63              dest_idx += 1
64          return smallest_number
65  def generate_test_cases(T) :
66      count = 1
67      while count <= T :
68          N = raw_input("")
69          N = N.split()
70          num_of_people = int(N[0])
71          max_grid_size = int(N[1])
72          coordinates = get_next_location(num_of_people)
73          x = int(coordinates[0])
74          y = int(coordinates[1])
75          print "Case #" + str(count) + ": " + str(x) + " " + str(y)
76          count += 1
77  T = eval(raw_input(""))
78  generate_test_cases(int(T))
```


**Question**: Which lines have control dependence over line `49` in function `get_next_location`? List all such lines.

**Output**:


Ground truth answer: yes