# [119. Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii)

[中文文档](/solution/0100-0199/0119.Pascal%27s%20Triangle%20II/README.md)

## Description

<p>Given an integer <code>rowIndex</code>, return the <code>rowIndex<sup>th</sup></code> (<strong>0-indexed</strong>) row of the <strong>Pascal&#39;s triangle</strong>.</p>

<p>In <strong>Pascal&#39;s triangle</strong>, each number is the sum of the two numbers directly above it as shown:</p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0100-0199/0119.Pascal%27s%20Triangle%20II/images/PascalTriangleAnimated2.gif" style="height:240px; width:260px" />
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> rowIndex = 3
<strong>Output:</strong> [1,3,3,1]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> rowIndex = 0
<strong>Output:</strong> [1]
</pre><p><strong class="example">Example 3:</strong></p>
<pre><strong>Input:</strong> rowIndex = 1
<strong>Output:</strong> [1,1]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>0 &lt;= rowIndex &lt;= 33</code></li>
</ul>

<p>&nbsp;</p>
<p><strong>Follow up:</strong> Could you optimize your algorithm to use only <code>O(rowIndex)</code> extra space?</p>

## Solutions

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### **Python3**

```python
class Solution:
    def getRow(self, rowIndex: int) -> List[int]:
        row = [1] * (rowIndex + 1)
        for i in range(2, rowIndex + 1):
            for j in range(i - 1, 0, -1):
                row[j] += row[j - 1]
        return row
```

### **Java**

```java
class Solution {
    public List<Integer> getRow(int rowIndex) {
        List<Integer> row = new ArrayList<>();
        for (int i = 0; i < rowIndex + 1; ++i) {
            row.add(1);
        }
        for (int i = 2; i < rowIndex + 1; ++i) {
            for (int j = i - 1; j > 0; --j) {
                row.set(j, row.get(j) + row.get(j - 1));
            }
        }
        return row;
    }
}
```

### **TypeScript**

```ts
function getRow(rowIndex: number): number[] {
    let ans = new Array(rowIndex + 1).fill(1);
    for (let i = 2; i < rowIndex + 1; ++i) {
        for (let j = i - 1; j > 0; --j) {
            ans[j] += ans[j - 1];
        }
    }
    return ans;
}
```

### **C++**

```cpp
class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<int> row(rowIndex + 1, 1);
        for (int i = 2; i < rowIndex + 1; ++i) {
            for (int j = i - 1; j > 0; --j) {
                row[j] += row[j - 1];
            }
        }
        return row;
    }
};
```

### **Go**

```go
func getRow(rowIndex int) []int {
	row := make([]int, rowIndex+1)
	row[0] = 1
	for i := 1; i <= rowIndex; i++ {
		for j := i; j > 0; j-- {
			row[j] += row[j-1]
		}
	}
	return row
}
```

### **Rust**

```rust
impl Solution {
    pub fn get_row(row_index: i32) -> Vec<i32> {
        let n = (row_index + 1) as usize;
        let mut res = vec![1; n];
        for i in 2..n {
            for j in (1..i).rev() {
                res[j] += res[j - 1];
            }
        }
        res
    }
}
```

### **...**

```

```

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