Problem Statement

You are given a string S, which represents a weather forecast for the seven days starting tomorrow.
The i-th of those seven days is forecast to be sunny if the i-th character of S is o, and rainy if that character is x.

Tell us whether the N-th day is forecast to be sunny.

Constraints

• N is an integer between 1 and 7 (inclusive).
• S is a string of length 7 consisting of o and x.

Sample Input 1

4
oooxoox

Sample Output 1

No

The forecast for each of the seven days starting tomorrow is as follows: sunny, sunny, sunny, rainy, sunny, sunny, rainy.
In particular, the fourth day is forecast to be rainy.

Sample Input 2

7
ooooooo

Sample Output 2

Yes

Problem Statement

You are given a string S ending with er or ist.
If S ends with er, print er; if it ends with ist, print ist.

Constraints

• 2 \le |S| \le 20
• S consists of lowercase English letters.
• S ends with er or ist.

Sample Input 1

atcoder

Sample Output 1

er

S="atcoder" ends with er.

Sample Input 2

tourist

Sample Output 2

ist

Sample Input 3

er

Sample Output 3

er

Problem Statement

The digit sum of a positive integer n is defined as the sum of the digits when n is represented in decimal. For example, the digit sum of 2026 is 2+0+2+6=10.

Find the number of positive integers not exceeding N whose digit sum is K.

Constraints

• 1\leq N,K \leq 10^5
• All input values are integers.

Sample Input 1

30 4

Sample Output 1

3

Among the positive integers not exceeding 30, there are three integers whose digit sum is 4: 4,13,22.

Sample Input 2

2026 10

Sample Output 2

121

Sample Input 3

99999 45

Sample Output 3

1

Problem Statement

There is a linear warehouse, which stores an even number of packages.
The layout of the warehouse is represented by a string S.
The warehouse has |S| sections, numbered 1,2,\dots,|S|, and the string S describes them as follows:

• When the i-th character of S is #, one package is placed in section i.
• When the i-th character of S is ., no package is placed in section i.

The warehouse has a robot, which repeats the following action until there are no more packages in the warehouse:

• Collect two packages from the sections with the smallest section numbers among the sections containing packages. The collected packages are carried out of the warehouse.

For each iteration, determine which sections of the warehouse the two packages that were carried out were originally located.

Constraints

• S is a string consisting of # and . with length between 2 and 1000, inclusive.
• The warehouse stores an even number of packages.
• The warehouse stores at least two packages.

Sample Input 1

.#.##..##.#.###....#

Sample Output 1

2,4
5,8
9,11
13,14
15,20

Packages are stored in sections 2,4,5,8,9,11,13,14,15,20.

• In the 1st iteration, packages from sections 2,4 are carried out.
• In the 2nd iteration, packages from sections 5,8 are carried out.
• In the 3rd iteration, packages from sections 9,11 are carried out.
• In the 4th iteration, packages from sections 13,14 are carried out.
• In the 5th iteration, packages from sections 15,20 are carried out.

Problem Statement

There is a 10^9-story building with N ladders.
Takahashi, who is on the 1-st (lowest) floor, wants to reach the highest floor possible by using ladders (possibly none).
The ladders are numbered from 1 to N, and ladder i connects the A_i-th and B_i-th floors. One can use ladder i in either direction to move from the A_i-th floor to the B_i-th floor or vice versa, but not between other floors.
Takahashi can freely move within the same floor, but cannot move between floors without using ladders.
What is the highest floor Takahashi can reach?

Constraints

• 1 \leq N \leq 2 \times 10^5
• 1 \leq A_i, B_i \leq 10^9
• A_i \neq B_i
• All values in the input are integers.

Sample Input 1

4
1 4
4 3
4 10
8 3

Sample Output 1

10

He can reach the 10-th floor by using ladder 1 to get to the 4-th floor and then ladder 3 to get to the 10-th floor.

Sample Input 2

6
1 3
1 5
1 12
3 5
3 12
5 12

Sample Output 2

12

Sample Input 3

3
500000000 600000000
600000000 700000000
700000000 800000000

Sample Output 3

1

He may be unable to move between floors.

Problem Statement

On a two-dimensional plane, Takahashi is initially at point (0, 0), and his initial health is H. M items to recover health are placed on the plane; the i-th of them is placed at (x_i,y_i).

Takahashi will make N moves. The i-th move is as follows.

1. Let (x,y) be his current coordinates. He consumes a health of 1 to move to the following point, depending on S_i, the i-th character of S:

   • (x+1,y) if S_i is R;
   • (x-1,y) if S_i is L;
   • (x,y+1) if S_i is U;
   • (x,y-1) if S_i is D.

2. If Takahashi's health has become negative, he collapses and stops moving. Otherwise, if an item is placed at the point he has moved to, and his health is strictly less than K, then he consumes the item there to make his health K.

Determine if Takahashi can complete the N moves without being stunned.

Constraints

• 1\leq N,M,H,K\leq 2\times 10^5
• S is a string of length N consisting of R, L, U, and D.
• |x_i|,|y_i| \leq 2\times 10^5
• (x_i, y_i) are pairwise distinct.
• All values in the input are integers, except for S.

Sample Input 1

4 2 3 1
RUDL
-1 -1
1 0

Sample Output 1

Yes

Initially, Takahashi's health is 3. We describe the moves below.

• 1-st move: S_i is R, so he moves to point (1,0). His health reduces to 2. Although an item is placed at point (1,0), he do not consume it because his health is no less than K=1.

• 2-nd move: S_i is U, so he moves to point (1,1). His health reduces to 1.

• 3-rd move: S_i is D, so he moves to point (1,0). His health reduces to 0. An item is placed at point (1,0), and his health is less than K=1, so he consumes the item to make his health 1.

• 4-th move: S_i is L, so he moves to point (0,0). His health reduces to 0.

Thus, he can make the 4 moves without collapsing, so Yes should be printed. Note that the health may reach 0.

Sample Input 2

5 2 1 5
LDRLD
0 0
-1 -1

Sample Output 2

No

Initially, Takahashi's health is 1. We describe the moves below.

• 1-st move: S_i is L, so he moves to point (-1,0). His health reduces to 0.

• 2-nd move: S_i is D, so he moves to point (-1,-1). His health reduces to -1. Now that the health is -1, he collapses and stops moving.

Thus, he will be stunned, so No should be printed.

Note that although there is an item at his initial point (0,0), he does not consume it before the 1-st move, because items are only consumed after a move.

Problem Statement

You are given an undirected graph with N vertices numbered 1 to N and M edges numbered 1 to M. Edge i connects vertex u_i and vertex v_i.

Determine whether every connected component in this graph satisfies the following condition.

• The connected component has the same number of vertices and edges.

Notes

An undirected graph is a graph with edges without direction.
A subgraph of a graph is a graph formed from a subset of vertices and edges of that graph.
A graph is connected when one can travel between every pair of vertices in the graph via edges.
A connected component is a connected subgraph that is not part of any larger connected subgraph.

Constraints

• 1 \leq N \leq 2 \times 10^5
• 0 \leq M \leq 2 \times 10^5
• 1 \leq u_i \leq v_i \leq N
• All values in the input are integers.

Sample Input 1

3 3
2 3
1 1
2 3

Sample Output 1

Yes

The graph has a connected component formed from just vertex 1, and another formed from vertices 2 and 3.
The former has one edge (edge 2), and the latter has two edges (edges 1 and 3), satisfying the condition.

Sample Input 2

5 5
1 2
2 3
3 4
3 5
1 5

Sample Output 2

Yes

Sample Input 3

13 16
7 9
7 11
3 8
1 13
11 11
6 11
8 13
2 11
3 3
8 12
9 11
1 11
5 13
3 12
6 9
1 10

Sample Output 3

No

Problem Statement

There is a tree with N vertices numbered 1 to N. The i-th edge connects vertices A_i and B_i.
Define the distance between vertices u and v as the number of edges in the path with endpoints at vertices u and v. (This path is uniquely determined.)

Solve the following problem for v = 1, 2, \dots, N.

• Among vertices 1, 2, \dots, N, output the number of the vertex that has the maximum distance from vertex v. If there are multiple vertices that satisfy the condition, output the vertex with the largest number.

Constraints

• 2 \leq N \leq 5 \times 10^5
• 1 \leq A_i \lt B_i \leq N
• The graph given in the input is a tree.
• All input values are integers.

Sample Input 1

3
1 2
2 3

Sample Output 1

3
3
1

The vertex with the maximum distance from vertex 1 is vertex 3.
The vertices with the maximum distance from vertex 2 are vertices 1 and 3. Among them, vertex 3, which has the larger number, is the answer.
The vertex with the maximum distance from vertex 3 is vertex 1.

Sample Input 2

5
1 2
2 3
2 4
1 5

Sample Output 2

4
5
5
5
4

Problem Statement

Consider a binary tree with N vertices numbered 1, 2, \ldots, N. Here, a binary tree is a rooted tree where each vertex has at most two children. Specifically, each vertex in a binary tree has at most one left child and at most one right child.

Determine whether there exists a binary tree rooted at Vertex 1 satisfying the conditions below, and present such a tree if it exists.

• The depth-first traversal of the tree in pre-order is (P_1, P_2, \ldots, P_N).
• The depth-first traversal of the tree in in-order is (I_1, I_2, \ldots, I_N).

Constraints

• 2 \leq N \leq 2 \times 10^5
• N is an integer.
• (P_1, P_2, \ldots, P_N) is a permutation of (1, 2, \ldots, N).
• (I_1, I_2, \ldots, I_N) is a permutation of (1, 2, \ldots, N).

Sample Input 1

6
1 3 5 6 4 2
3 5 1 4 6 2

Sample Output 1

3 6
0 0
0 5
0 0
0 0
4 2

The binary tree rooted at Vertex 1 shown in the following image satisfies the conditions.

Sample Input 2

2
2 1
1 2

Sample Output 2

-1

No binary tree rooted at Vertex 1 satisfies the conditions, so -1 should be printed.