From f5af1a33b3cfdc40de3b563039690d76320dbc8a Mon Sep 17 00:00:00 2001 From: yanglbme Date: Fri, 1 Aug 2025 07:13:19 +0800 Subject: [PATCH] feat: add solutions to lc problem: No.0118 No.0118.Pascal's Triangle --- .../0118.Pascal's Triangle/README.md | 61 +++++++++++------- .../0118.Pascal's Triangle/README_EN.md | 63 ++++++++++++------- .../0118.Pascal's Triangle/Solution.cpp | 4 +- .../0118.Pascal's Triangle/Solution.cs | 14 +++++ .../0118.Pascal's Triangle/Solution.go | 4 +- .../0118.Pascal's Triangle/Solution.java | 4 +- .../0118.Pascal's Triangle/Solution.js | 4 +- .../0118.Pascal's Triangle/Solution.rs | 20 +++--- .../0118.Pascal's Triangle/Solution.ts | 4 +- 9 files changed, 109 insertions(+), 69 deletions(-) create mode 100644 solution/0100-0199/0118.Pascal's Triangle/Solution.cs diff --git a/solution/0100-0199/0118.Pascal's Triangle/README.md b/solution/0100-0199/0118.Pascal's Triangle/README.md index fd03f8d453b2d..d15d69697e1bf 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/README.md +++ b/solution/0100-0199/0118.Pascal's Triangle/README.md @@ -57,7 +57,7 @@ tags: 我们先创建一个答案数组 $f$，然后将 $f$ 的第一行元素设为 $[1]$。接下来，我们从第二行开始，每一行的开头和结尾元素都是 $1$，其它 $f[i][j] = f[i - 1][j - 1] + f[i - 1][j]$。 -时间复杂度 $O(n^2)$，空间复杂度 $O(n^2)$。其中 $n$ 是行数。 +时间复杂度 $O(n^2)$，其中 $n$ 为给定的行数。忽略答案的空间消耗，空间复杂度 $O(1)$。 @@ -83,8 +83,8 @@ class Solution { for (int i = 0; i < numRows - 1; ++i) { List g = new ArrayList<>(); g.add(1); - for (int j = 0; j < f.get(i).size() - 1; ++j) { - g.add(f.get(i).get(j) + f.get(i).get(j + 1)); + for (int j = 1; j < f.get(i).size(); ++j) { + g.add(f.get(i).get(j - 1) + f.get(i).get(j)); } g.add(1); f.add(g); @@ -105,8 +105,8 @@ public: for (int i = 0; i < numRows - 1; ++i) { vector g; g.push_back(1); - for (int j = 0; j < f[i].size() - 1; ++j) { - g.push_back(f[i][j] + f[i][j + 1]); + for (int j = 1; j < f[i].size(); ++j) { + g.push_back(f[i][j - 1] + f[i][j]); } g.push_back(1); f.push_back(g); @@ -123,8 +123,8 @@ func generate(numRows int) [][]int { f := [][]int{[]int{1}} for i := 0; i < numRows-1; i++ { g := []int{1} - for j := 0; j < len(f[i])-1; j++ { - g = append(g, f[i][j]+f[i][j+1]) + for j := 1; j < len(f[i]); j++ { + g = append(g, f[i][j-1]+f[i][j]) } g = append(g, 1) f = append(f, g) @@ -140,8 +140,8 @@ function generate(numRows: number): number[][] { const f: number[][] = [[1]]; for (let i = 0; i < numRows - 1; ++i) { const g: number[] = [1]; - for (let j = 0; j < f[i].length - 1; ++j) { - g.push(f[i][j] + f[i][j + 1]); + for (let j = 1; j < f[i].length; ++j) { + g.push(f[i][j - 1] + f[i][j]); } g.push(1); f.push(g); @@ -154,21 +154,17 @@ function generate(numRows: number): number[][] { ```rust impl Solution { - #[allow(dead_code)] pub fn generate(num_rows: i32) -> Vec> { - let mut ret_vec: Vec> = Vec::new(); - let mut cur_vec: Vec = Vec::new(); - - for i in 0..num_rows as usize { - let mut new_vec: Vec = vec![1; i + 1]; - for j in 1..i { - new_vec[j] = cur_vec[j - 1] + cur_vec[j]; + let mut f = vec![vec![1]]; + for i in 1..num_rows { + let mut g = vec![1]; + for j in 1..f[i as usize - 1].len() { + g.push(f[i as usize - 1][j - 1] + f[i as usize - 1][j]); } - cur_vec = new_vec.clone(); - ret_vec.push(new_vec); + g.push(1); + f.push(g); } - - ret_vec + f } } ``` @@ -184,8 +180,8 @@ var generate = function (numRows) { const f = [[1]]; for (let i = 0; i < numRows - 1; ++i) { const g = [1]; - for (let j = 0; j < f[i].length - 1; ++j) { - g.push(f[i][j] + f[i][j + 1]); + for (let j = 1; j < f[i].length; ++j) { + g.push(f[i][j - 1] + f[i][j]); } g.push(1); f.push(g); @@ -194,6 +190,25 @@ var generate = function (numRows) { }; ``` +#### C# + +```cs +public class Solution { + public IList> Generate(int numRows) { + var f = new List> { new List { 1 } }; + for (int i = 1; i < numRows; ++i) { + var g = new List { 1 }; + for (int j = 1; j < f[i - 1].Count; ++j) { + g.Add(f[i - 1][j - 1] + f[i - 1][j]); + } + g.Add(1); + f.Add(g); + } + return f; + } +} +``` + diff --git a/solution/0100-0199/0118.Pascal's Triangle/README_EN.md b/solution/0100-0199/0118.Pascal's Triangle/README_EN.md index f98f9bb00258a..6f0ebd1725081 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/README_EN.md +++ b/solution/0100-0199/0118.Pascal's Triangle/README_EN.md @@ -44,9 +44,9 @@ tags: ### Solution 1: Simulation -First, we create an answer array $f$, and then set the first row of $f$ to $[1]$. Next, starting from the second row, the first and last elements of each row are $1$, and the other elements are calculated by $f[i][j] = f[i - 1][j - 1] + f[i - 1][j]$. +We first create an answer array $f$, then set the first row of $f$ to $[1]$. Next, starting from the second row, the first and last elements of each row are $1$, and for other elements $f[i][j] = f[i - 1][j - 1] + f[i - 1][j]$. -The time complexity is $O(n^2)$, and the space complexity is $O(n^2)$. Here, $n$ is the number of rows. +The time complexity is $O(n^2)$, where $n$ is the given number of rows. Ignoring the space consumption of the answer, the space complexity is $O(1)$. @@ -72,8 +72,8 @@ class Solution { for (int i = 0; i < numRows - 1; ++i) { List g = new ArrayList<>(); g.add(1); - for (int j = 0; j < f.get(i).size() - 1; ++j) { - g.add(f.get(i).get(j) + f.get(i).get(j + 1)); + for (int j = 1; j < f.get(i).size(); ++j) { + g.add(f.get(i).get(j - 1) + f.get(i).get(j)); } g.add(1); f.add(g); @@ -94,8 +94,8 @@ public: for (int i = 0; i < numRows - 1; ++i) { vector g; g.push_back(1); - for (int j = 0; j < f[i].size() - 1; ++j) { - g.push_back(f[i][j] + f[i][j + 1]); + for (int j = 1; j < f[i].size(); ++j) { + g.push_back(f[i][j - 1] + f[i][j]); } g.push_back(1); f.push_back(g); @@ -112,8 +112,8 @@ func generate(numRows int) [][]int { f := [][]int{[]int{1}} for i := 0; i < numRows-1; i++ { g := []int{1} - for j := 0; j < len(f[i])-1; j++ { - g = append(g, f[i][j]+f[i][j+1]) + for j := 1; j < len(f[i]); j++ { + g = append(g, f[i][j-1]+f[i][j]) } g = append(g, 1) f = append(f, g) @@ -129,8 +129,8 @@ function generate(numRows: number): number[][] { const f: number[][] = [[1]]; for (let i = 0; i < numRows - 1; ++i) { const g: number[] = [1]; - for (let j = 0; j < f[i].length - 1; ++j) { - g.push(f[i][j] + f[i][j + 1]); + for (let j = 1; j < f[i].length; ++j) { + g.push(f[i][j - 1] + f[i][j]); } g.push(1); f.push(g); @@ -143,21 +143,17 @@ function generate(numRows: number): number[][] { ```rust impl Solution { - #[allow(dead_code)] pub fn generate(num_rows: i32) -> Vec> { - let mut ret_vec: Vec> = Vec::new(); - let mut cur_vec: Vec = Vec::new(); - - for i in 0..num_rows as usize { - let mut new_vec: Vec = vec![1; i + 1]; - for j in 1..i { - new_vec[j] = cur_vec[j - 1] + cur_vec[j]; + let mut f = vec![vec![1]]; + for i in 1..num_rows { + let mut g = vec![1]; + for j in 1..f[i as usize - 1].len() { + g.push(f[i as usize - 1][j - 1] + f[i as usize - 1][j]); } - cur_vec = new_vec.clone(); - ret_vec.push(new_vec); + g.push(1); + f.push(g); } - - ret_vec + f } } ``` @@ -173,8 +169,8 @@ var generate = function (numRows) { const f = [[1]]; for (let i = 0; i < numRows - 1; ++i) { const g = [1]; - for (let j = 0; j < f[i].length - 1; ++j) { - g.push(f[i][j] + f[i][j + 1]); + for (let j = 1; j < f[i].length; ++j) { + g.push(f[i][j - 1] + f[i][j]); } g.push(1); f.push(g); @@ -183,6 +179,25 @@ var generate = function (numRows) { }; ``` +#### C# + +```cs +public class Solution { + public IList> Generate(int numRows) { + var f = new List> { new List { 1 } }; + for (int i = 1; i < numRows; ++i) { + var g = new List { 1 }; + for (int j = 1; j < f[i - 1].Count; ++j) { + g.Add(f[i - 1][j - 1] + f[i - 1][j]); + } + g.Add(1); + f.Add(g); + } + return f; + } +} +``` + diff --git a/solution/0100-0199/0118.Pascal's Triangle/Solution.cpp b/solution/0100-0199/0118.Pascal's Triangle/Solution.cpp index 62f2014da6b74..d67f423dcce71 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/Solution.cpp +++ b/solution/0100-0199/0118.Pascal's Triangle/Solution.cpp @@ -6,8 +6,8 @@ class Solution { for (int i = 0; i < numRows - 1; ++i) { vector g; g.push_back(1); - for (int j = 0; j < f[i].size() - 1; ++j) { - g.push_back(f[i][j] + f[i][j + 1]); + for (int j = 1; j < f[i].size(); ++j) { + g.push_back(f[i][j - 1] + f[i][j]); } g.push_back(1); f.push_back(g); diff --git a/solution/0100-0199/0118.Pascal's Triangle/Solution.cs b/solution/0100-0199/0118.Pascal's Triangle/Solution.cs new file mode 100644 index 0000000000000..51f9c369512a8 --- /dev/null +++ b/solution/0100-0199/0118.Pascal's Triangle/Solution.cs @@ -0,0 +1,14 @@ +public class Solution { + public IList> Generate(int numRows) { + var f = new List> { new List { 1 } }; + for (int i = 1; i < numRows; ++i) { + var g = new List { 1 }; + for (int j = 1; j < f[i - 1].Count; ++j) { + g.Add(f[i - 1][j - 1] + f[i - 1][j]); + } + g.Add(1); + f.Add(g); + } + return f; + } +} diff --git a/solution/0100-0199/0118.Pascal's Triangle/Solution.go b/solution/0100-0199/0118.Pascal's Triangle/Solution.go index a754b007af70f..6505391e78e34 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/Solution.go +++ b/solution/0100-0199/0118.Pascal's Triangle/Solution.go @@ -2,8 +2,8 @@ func generate(numRows int) [][]int { f := [][]int{[]int{1}} for i := 0; i < numRows-1; i++ { g := []int{1} - for j := 0; j < len(f[i])-1; j++ { - g = append(g, f[i][j]+f[i][j+1]) + for j := 1; j < len(f[i]); j++ { + g = append(g, f[i][j-1]+f[i][j]) } g = append(g, 1) f = append(f, g) diff --git a/solution/0100-0199/0118.Pascal's Triangle/Solution.java b/solution/0100-0199/0118.Pascal's Triangle/Solution.java index 550edb73b4d18..6af3d6d7e377b 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/Solution.java +++ b/solution/0100-0199/0118.Pascal's Triangle/Solution.java @@ -5,8 +5,8 @@ public List> generate(int numRows) { for (int i = 0; i < numRows - 1; ++i) { List g = new ArrayList<>(); g.add(1); - for (int j = 0; j < f.get(i).size() - 1; ++j) { - g.add(f.get(i).get(j) + f.get(i).get(j + 1)); + for (int j = 1; j < f.get(i).size(); ++j) { + g.add(f.get(i).get(j - 1) + f.get(i).get(j)); } g.add(1); f.add(g); diff --git a/solution/0100-0199/0118.Pascal's Triangle/Solution.js b/solution/0100-0199/0118.Pascal's Triangle/Solution.js index a00aea7a5b57a..0308e343d8bea 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/Solution.js +++ b/solution/0100-0199/0118.Pascal's Triangle/Solution.js @@ -6,8 +6,8 @@ var generate = function (numRows) { const f = [[1]]; for (let i = 0; i < numRows - 1; ++i) { const g = [1]; - for (let j = 0; j < f[i].length - 1; ++j) { - g.push(f[i][j] + f[i][j + 1]); + for (let j = 1; j < f[i].length; ++j) { + g.push(f[i][j - 1] + f[i][j]); } g.push(1); f.push(g); diff --git a/solution/0100-0199/0118.Pascal's Triangle/Solution.rs b/solution/0100-0199/0118.Pascal's Triangle/Solution.rs index 695167530c1f3..829e3d11e44b5 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/Solution.rs +++ b/solution/0100-0199/0118.Pascal's Triangle/Solution.rs @@ -1,18 +1,14 @@ impl Solution { - #[allow(dead_code)] pub fn generate(num_rows: i32) -> Vec> { - let mut ret_vec: Vec> = Vec::new(); - let mut cur_vec: Vec = Vec::new(); - - for i in 0..num_rows as usize { - let mut new_vec: Vec = vec![1; i + 1]; - for j in 1..i { - new_vec[j] = cur_vec[j - 1] + cur_vec[j]; + let mut f = vec![vec![1]]; + for i in 1..num_rows { + let mut g = vec![1]; + for j in 1..f[i as usize - 1].len() { + g.push(f[i as usize - 1][j - 1] + f[i as usize - 1][j]); } - cur_vec = new_vec.clone(); - ret_vec.push(new_vec); + g.push(1); + f.push(g); } - - ret_vec + f } } diff --git a/solution/0100-0199/0118.Pascal's Triangle/Solution.ts b/solution/0100-0199/0118.Pascal's Triangle/Solution.ts index 91203940b7925..09857ec026b01 100644 --- a/solution/0100-0199/0118.Pascal's Triangle/Solution.ts +++ b/solution/0100-0199/0118.Pascal's Triangle/Solution.ts @@ -2,8 +2,8 @@ function generate(numRows: number): number[][] { const f: number[][] = [[1]]; for (let i = 0; i < numRows - 1; ++i) { const g: number[] = [1]; - for (let j = 0; j < f[i].length - 1; ++j) { - g.push(f[i][j] + f[i][j + 1]); + for (let j = 1; j < f[i].length; ++j) { + g.push(f[i][j - 1] + f[i][j]); } g.push(1); f.push(g);