[INSTRUCTIONS]

You are a program-analysis assistant. Perform a **static** data-dependence analysis on a given code snippet, treating each branch or loop condition as potentially taking any outcome, without using semantic or symbolic execution to prune paths.


## 1. Data Dependence Definition

   Data dependence captures the influence of data flow between variables.

   We denote each variable instance as `(var,lineNumber)`, meaning the variable `var` defined or updated at `lineNumber`.

   >  **Direct Data Dependence**
   A variable instance `(varB,lineB)` is **directly** data-dependent on `(varA,lineA)` if `lineA` writes to `varA`. Then, without overwritting the value of `varA`, `lineB` reads `varA` and compute the value of `varB`. In other words, the value of `(varB,lineB)` relies on the value produced at `(varA,lineA)`. In addition, changing the execution order of `(varA,lineA)` and `(varB,lineB)` would alter their results.


   A variable instance `(varB,lineB)` is data-dependent on `(varA,lineA)` if there is a **transitive** (indirect) chain of **direct** data dependencies from `(varA,lineA)` to `(varB,lineB)`. This is equivalent to saying that `(varA,lineA)` has data dependence over `(varB,lineB)`, meaning the value written at `(varA,lineA)` can propagate to `(varB,lineB)` through a sequence of read/write operations.


## 2. Output Format
   When asked "Does `(varA,lineA)` have data dependence over `(varB,lineB)`? If so, provide one feasible trace.": 
   - If data dependence exists, respond:
   ```json
   {
   "DataDependence": true,
   "Trace": [
      { "from": ["varA", lineA], "to": ["varX", lineX] },
      ...
      { "from": ["varY", lineY], "to": ["varB", lineB] }
      ]
   }
   ```

   -  If no data dependence exists, respond:
   ```json
   {
   "DataDependence": false
   }
   ```
   
   A **trace** represents a **transitive data flow**, where each item represents a **direct** data dependence edge. The full trace should begin with `(varA,lineA)` and end with `(varB,lineB)`.

   You only need to provide **one** valid chain of data dependence if you conclude a data dependence exists, even if multiple possible chains exist. 


## 3. Intraprocedural Data 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    total = 0
2    value = 1
3    step = value
4    if step > 1:
5        value += 3
6    while total <= 10:
7        total += value
8        difference = total - step
9        step += 1
10   final_result = total * 2
```


#### Example Question 1.1:
Does `(value,2)` have data dependence over `(step,9)`? If so, provide a trace.

**Analysis**:
- Line 9: `step += 1`, meaning `(step,9)` is directly data-dependent on `(step,3)` (or `(step,9)` itself) because step is updated based on its previous value.
- Line 3: `step = value`, meaning `(step,3)` is directly data-dependent on `(value,2)`.
Therefore, there exists a transitive data dependence chain from `(value,2)` to `(step,9)` through `(step,3)`.


**Output**:
```json
{
  "DataDependence": true,
  "Trace": [
    { "from": ["value", 2], "to": ["step", 3] },
    { "from": ["step", 3], "to": ["step", 9] }
  ]
}
```

#### Example Question 1.2 
Does `(value,2)` have data dependence over `(total,7)`? If so, provide a trace.

**Analysis**:
- Line 7: `total += value`, meaning `(total,7)` reads `value` from either `(value,2)` or `(value,5)`.
- Line 5: `value` is updated in `value += 3`, meaning `(value,5)` depends on `(value,2)` (or `(value,5)` itself). However, this update is inside an if statement, which means it may or may not execute depending on runtime conditions.
- Line 2: value is initialized at `(value,2)`.


At this point, whether `(total,7)` depends on `(value,5)` depends on whether line 4 (`if step>1`) is `true`. Since this is a static analysis, all possible paths are considered without analyzing actual reachability. This means line 5 is treated as both possibly executed and possibly not executed.

- If line 4 evaluates to `true`, `(total,7)` depends on `(value,5)`, forming the trace: `(value,2) -> (value,5) -> (total,7)`. 
- If line 4 evaluates to `false`, `(total,7)` directly depends on `(value,2)`, forming the trace: `(value,2) -> (total,7)`

Therefore, the answer is yes.
Only one valid trace is required for the output. 

**Output**:
```json
{
  "DataDependence": true,
  "Trace": [
    { "from": ["value", 2], "to": ["value", 5] },
    { "from": ["value", 5], "to": ["total", 7] }
  ]
}

```



#### Example Question 1.3
Does `(step,3)` have data dependence over `(final_result,10)`? If so, provide a trace.  

**Analysis**:
Since there is no direct or transitive data dependence between `(step,3)` and `(final_result,10)`, the answer is No.

**Output**:
```json
{
  "DataDependence": false
}
```

**Analysis**:


### Example 2

```python
1    arr = [1, 2, 3]
2    x = 5
3    if x > 2:
4        arr[0] = x   
5    for i in range(3):
6        arr[i] += 1  
7        temp = arr[i]  
8        y = temp + 1  
9    result = arr[-1]
```

#### Example Question 2.1:
Does `(x,2)` have data dependence over `(arr,6)`? If so, provide a trace.

**Analysis**
- Line 6: `arr[i] += 1` modifies `arr[i]`, but i varies during the loop execution.
   - If `i == 0`, `arr[i]` refers to `arr[0]`, which was updated in line 4 (or line 6 itself), establishing a dependence chain `(arr,4)` -> `(arr,6)`.
   - If `i != 0`, `arr[i]` does not refer to `arr[0]`, meaning it depend on `(arr,1)` (or `(arr,6)` itself), not `(arr,4)`.
   - However, since static analysis considers all possible paths without resolving i’s runtime value, we must assume `arr[i]` could be `arr[0]`, leading to a possible dependence.
- Line 4: `arr[0] = x`, meaning `(arr,4)` depends on `(x,2)`.
- Line 2: `x` is initialized at `(x,2)`.
- Since there is a transitive chain of direct data dependence: `(x,2)->(arr,4)->(arr,6)`, the answer is yes.


**Output**:
```json
{
  "DataDependence": true,
  "Trace": [
    { "from": ["x", 2], "to": ["arr", 4] },
    { "from": ["arr", 4], "to": ["arr", 6] }
  ]
}
```


#### Example Question 2.2:
Does `(i,5)` have data dependence over `(temp,7)`? If so, provide a trace.

**Analysis**:
- Line 7: `temp = arr[i]`, meaning temp depends on `i`, since `i` determines which element of arr is accessed.
- Line 5: `i` is initialized and iterates over the range 0 to 3.
- Since there is a transitive chain of direct data dependence: `(i,5)->(temp,7)`, the answer is yes.


**Output**:
```json
{
  "DataDependence": true,
  "Trace": [
    { "from": ["i", 5], "to": ["temp", 7] }
  ]
}
```

#### Example Question 2.3:
Does `(i,5)` have data dependence over `(result,9)`? If so, provide a trace.

**Analysis**:
- Line 9: `result = arr[-1]`, meaning result depends on `arr[-1]`, which is arr[2], possibly get updated at line 6 (or line 1).
- Line 6: `arr[i] += 1`, meaning `arr[i]` is modified based on the value of `i`.
- Line 5: `i` iterates over 0 to 3.
- Since there is a transitive chain of direct data dependence: `(i,5)->(arr,6)->(result,9)`, the answer is yes.


**Output**:
```json
{
  "DataDependence": true,
  "Trace": [
    { "from": ["i", 5], "to": ["arr", 6] },
    { "from": ["arr", 6], "to": ["result", 9] }
  ]
}
```

---

[YOUR TURN]

Below is **your target snippet**. 

```Java
1   import java.io.*;
2   import java.util.*;
3   public class Main {
4       static int N;
5       static int[] t;
6       static int[] v;
7       static int[] maxv;
8       public static void main(String[] args) throws IOException {
9           int totalt = 0;
10          MyScanner sc = new MyScanner(System.in);
11          int n = sc.nextInt();
12          t = new int[n];
13          v = new int[n];
14          for (int i = 0; i < n; i++) {
15              t[i] = sc.nextInt();
16              totalt += t[i];
17          }
18          for (int i = 0; i < n; i++) {
19              v[i] = sc.nextInt();
20          }
21          maxv = new int[totalt + 1];
22          int[] ctr = new int[totalt + 1];
23          Arrays.fill(maxv, -1);
24          maxv[0] = 0;
25          maxv[totalt] = 0;
26          int tidx = n - 1;
27          int mov = 0;
28          for (int i = totalt - 1; i > 0; i--) {
29              mov++;
30              maxv[i] = Math.min(maxv[i + 1] + 1, v[tidx]);
31              ctr[i] = v[tidx];
32              if (mov == t[tidx]){
33                  mov = 0;
34                  tidx--;
35              }
36          }
37          long size = 0;
38          long btt = 0;
39          int prevHei = 0;
40          int ttt = 0;
41          int curHei = 0;
42          int prepre = 0;
43          int perform = 0; 
44          for (int i = 1; i < totalt + 1; i++) {
45              int mv = maxv[i];
46              switch (perform){
47                  case 0:
48                      if (mv >= curHei + 1){
49                          curHei++;
50                          ttt++;
51                      } else {
52                          size += (curHei + prevHei) * ttt;
53                          prevHei = curHei;
54                          ttt = 0;
55                          if (mv == curHei){
56                              if (maxv[i + 1] == curHei - 1 && ctr[i + 1] > curHei){
57                                  btt += 1;
58                              }
59                              perform = 1;
60                          } else {
61                              perform = 2;
62                          }
63                          prepre = 0;
64                          i--;
65                      }
66                      break;
67                  case 1:
68                      if (mv == curHei){
69                          ttt++;
70                      } else {
71                          size += curHei * ttt * 2;
72                          ttt = 0;
73                          prevHei = curHei;
74                          if (mv > curHei){
75                              perform = 0;
76                              size += curHei * 2;
77                              i++;
78                          } else {
79                              perform = 2;
80                              if (prepre == 0){
81                              }
82                          }
83                          i--;
84                      }
85                      break;
86                  case 2:
87                      if (mv == curHei - 1){
88                          curHei--;
89                          ttt++;
90                      } else {
91                          size += (prevHei + curHei) * ttt;
92                          prevHei = curHei;
93                          ttt = 0;
94                          if (mv == curHei){
95                              perform = 1;
96                          } else {
97                              perform = 0;
98                          }
99                          i--;
100                      }
101                      prepre = 2;
102                      break;
103              }
104          }
105          size += (prevHei + curHei) * ttt;
106          System.out.println((size+0.0)/ 2 + (btt+0.0)/4);
107      }
108      static class MyScanner {
109          StringTokenizer st;
110          BufferedReader br;
111          public MyScanner(InputStream s){  br = new BufferedReader(new InputStreamReader(s));}
112          public MyScanner(FileReader s) throws FileNotFoundException {br = new BufferedReader(s);}
113          public String next() throws IOException
114          {
115              while (st == null || !st.hasMoreTokens())
116                  st = new StringTokenizer(br.readLine());
117              return st.nextToken();
118          }
119          public int nextInt() throws IOException {return Integer.parseInt(next());}
120          public long nextLong() throws IOException {return Long.parseLong(next());}
121          public String nextLine() throws IOException {return br.readLine();}
122          public double nextDouble() throws IOException { return Double.parseDouble(next()); }
123          public boolean ready() throws IOException {return br.ready();}
124      }
125  }
```


**Question**: Does `(prepre,42)` have data dependence over `(prevHei,73)` in function `main`? If so, provide a trace.

**Output**:


Ground truth answer: no