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Merged
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Jul 16, 2025
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feat: add solutions to lc problem: No.3203 #4572

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87 changes: 86 additions & 1 deletion solution/3200-3299/3203.Find Minimum Diameter After Merging Two Trees/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -211,7 +211,7 @@ public:
func minimumDiameterAfterMerge(edges1 [][]int, edges2 [][]int) int {
d1 := treeDiameter(edges1)
d2 := treeDiameter(edges2)
return max(max(d1, d2), (d1+1)/2+(d2+1)/2+1)
return max(d1, d2, (d1+1)/2+(d2+1)/2+1)
}

func treeDiameter(edges [][]int) (ans int) {
Expand Down Expand Up @@ -275,6 +275,91 @@ function treeDiameter(edges: number[][]): number {
}
```

#### Rust

```rust
impl Solution {
pub fn minimum_diameter_after_merge(edges1: Vec<Vec<i32>>, edges2: Vec<Vec<i32>>) -> i32 {
let d1 = Self::tree_diameter(&edges1);
let d2 = Self::tree_diameter(&edges2);
d1.max(d2).max((d1 + 1) / 2 + (d2 + 1) / 2 + 1)
}

fn tree_diameter(edges: &Vec<Vec<i32>>) -> i32 {
let n = edges.len() + 1;
let mut g = vec![vec![]; n];
for e in edges {
let a = e[0] as usize;
let b = e[1] as usize;
g[a].push(b);
g[b].push(a);
}
let mut ans = 0;
let mut a = 0;
fn dfs(g: &Vec<Vec<usize>>, i: usize, fa: isize, t: i32, ans: &mut i32, a: &mut usize) {
for &j in &g[i] {
if j as isize != fa {
dfs(g, j, i as isize, t + 1, ans, a);
}
}
if *ans < t {
*ans = t;
*a = i;
}
}
dfs(&g, 0, -1, 0, &mut ans, &mut a);
dfs(&g, a, -1, 0, &mut ans, &mut a);
ans
}
}
```

#### C#

```cs
public class Solution {
private List<int>[] g;
private int ans;
private int a;

public int MinimumDiameterAfterMerge(int[][] edges1, int[][] edges2) {
int d1 = TreeDiameter(edges1);
int d2 = TreeDiameter(edges2);
return Math.Max(Math.Max(d1, d2), (d1 + 1) / 2 + (d2 + 1) / 2 + 1);
}

public int TreeDiameter(int[][] edges) {
int n = edges.Length + 1;
g = new List<int>[n];
for (int k = 0; k < n; ++k) {
g[k] = new List<int>();
}
ans = 0;
a = 0;
foreach (var e in edges) {
int a = e[0], b = e[1];
g[a].Add(b);
g[b].Add(a);
}
Dfs(0, -1, 0);
Dfs(a, -1, 0);
return ans;
}

private void Dfs(int i, int fa, int t) {
foreach (int j in g[i]) {
if (j != fa) {
Dfs(j, i, t + 1);
}
}
if (ans < t) {
ans = t;
a = i;
}
}
}
```

<!-- tabs:end -->

<!-- solution:end -->
Expand Down
87 changes: 86 additions & 1 deletion solution/3200-3299/3203.Find Minimum Diameter After Merging Two Trees/README_EN.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -209,7 +209,7 @@ public:
func minimumDiameterAfterMerge(edges1 [][]int, edges2 [][]int) int {
d1 := treeDiameter(edges1)
d2 := treeDiameter(edges2)
return max(max(d1, d2), (d1+1)/2+(d2+1)/2+1)
return max(d1, d2, (d1+1)/2+(d2+1)/2+1)
}

func treeDiameter(edges [][]int) (ans int) {
Expand Down Expand Up @@ -273,6 +273,91 @@ function treeDiameter(edges: number[][]): number {
}
```

#### Rust

```rust
impl Solution {
pub fn minimum_diameter_after_merge(edges1: Vec<Vec<i32>>, edges2: Vec<Vec<i32>>) -> i32 {
let d1 = Self::tree_diameter(&edges1);
let d2 = Self::tree_diameter(&edges2);
d1.max(d2).max((d1 + 1) / 2 + (d2 + 1) / 2 + 1)
}

fn tree_diameter(edges: &Vec<Vec<i32>>) -> i32 {
let n = edges.len() + 1;
let mut g = vec![vec![]; n];
for e in edges {
let a = e[0] as usize;
let b = e[1] as usize;
g[a].push(b);
g[b].push(a);
}
let mut ans = 0;
let mut a = 0;
fn dfs(g: &Vec<Vec<usize>>, i: usize, fa: isize, t: i32, ans: &mut i32, a: &mut usize) {
for &j in &g[i] {
if j as isize != fa {
dfs(g, j, i as isize, t + 1, ans, a);
}
}
if *ans < t {
*ans = t;
*a = i;
}
}
dfs(&g, 0, -1, 0, &mut ans, &mut a);
dfs(&g, a, -1, 0, &mut ans, &mut a);
ans
}
}
```

#### C#

```cs
public class Solution {
private List<int>[] g;
private int ans;
private int a;

public int MinimumDiameterAfterMerge(int[][] edges1, int[][] edges2) {
int d1 = TreeDiameter(edges1);
int d2 = TreeDiameter(edges2);
return Math.Max(Math.Max(d1, d2), (d1 + 1) / 2 + (d2 + 1) / 2 + 1);
}

public int TreeDiameter(int[][] edges) {
int n = edges.Length + 1;
g = new List<int>[n];
for (int k = 0; k < n; ++k) {
g[k] = new List<int>();
}
ans = 0;
a = 0;
foreach (var e in edges) {
int a = e[0], b = e[1];
g[a].Add(b);
g[b].Add(a);
}
Dfs(0, -1, 0);
Dfs(a, -1, 0);
return ans;
}

private void Dfs(int i, int fa, int t) {
foreach (int j in g[i]) {
if (j != fa) {
Dfs(j, i, t + 1);
}
}
if (ans < t) {
ans = t;
a = i;
}
}
}
```

<!-- tabs:end -->

<!-- solution:end -->
Expand Down
41 changes: 41 additions & 0 deletions solution/3200-3299/3203.Find Minimum Diameter After Merging Two Trees/Solution.cs
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Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,41 @@
public class Solution {
private List<int>[] g;
private int ans;
private int a;

public int MinimumDiameterAfterMerge(int[][] edges1, int[][] edges2) {
int d1 = TreeDiameter(edges1);
int d2 = TreeDiameter(edges2);
return Math.Max(Math.Max(d1, d2), (d1 + 1) / 2 + (d2 + 1) / 2 + 1);
}

public int TreeDiameter(int[][] edges) {
int n = edges.Length + 1;
g = new List<int>[n];
for (int k = 0; k < n; ++k) {
g[k] = new List<int>();
}
ans = 0;
a = 0;
foreach (var e in edges) {
int a = e[0], b = e[1];
g[a].Add(b);
g[b].Add(a);
}
Dfs(0, -1, 0);
Dfs(a, -1, 0);
return ans;
}

private void Dfs(int i, int fa, int t) {
foreach (int j in g[i]) {
if (j != fa) {
Dfs(j, i, t + 1);
}
}
if (ans < t) {
ans = t;
a = i;
}
}
}
2 changes: 1 addition & 1 deletion solution/3200-3299/3203.Find Minimum Diameter After Merging Two Trees/Solution.go
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
func minimumDiameterAfterMerge(edges1 [][]int, edges2 [][]int) int {
d1 := treeDiameter(edges1)
d2 := treeDiameter(edges2)
return max(max(d1, d2), (d1+1)/2+(d2+1)/2+1)
return max(d1, d2, (d1+1)/2+(d2+1)/2+1)
}

func treeDiameter(edges [][]int) (ans int) {
Expand Down
34 changes: 34 additions & 0 deletions solution/3200-3299/3203.Find Minimum Diameter After Merging Two Trees/Solution.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
impl Solution {
pub fn minimum_diameter_after_merge(edges1: Vec<Vec<i32>>, edges2: Vec<Vec<i32>>) -> i32 {
let d1 = Self::tree_diameter(&edges1);
let d2 = Self::tree_diameter(&edges2);
d1.max(d2).max((d1 + 1) / 2 + (d2 + 1) / 2 + 1)
}

fn tree_diameter(edges: &Vec<Vec<i32>>) -> i32 {
let n = edges.len() + 1;
let mut g = vec![vec![]; n];
for e in edges {
let a = e[0] as usize;
let b = e[1] as usize;
g[a].push(b);
g[b].push(a);
}
let mut ans = 0;
let mut a = 0;
fn dfs(g: &Vec<Vec<usize>>, i: usize, fa: isize, t: i32, ans: &mut i32, a: &mut usize) {
for &j in &g[i] {
if j as isize != fa {
dfs(g, j, i as isize, t + 1, ans, a);
}
}
if *ans < t {
*ans = t;
*a = i;
}
}
dfs(&g, 0, -1, 0, &mut ans, &mut a);
dfs(&g, a, -1, 0, &mut ans, &mut a);
ans
}
}