CSES - Shortest Routes II

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Gửi bài giải

Điểm: 1,00 (OI)
Giới hạn thời gian: 1.0s
Giới hạn bộ nhớ: 512M
Input: stdin
Output: stdout

Nguồn bài:
https://cses.fi/problemset/task/1672
Dạng bài
Ngôn ngữ cho phép
C, C++, Java, Kotlin, Pascal, PyPy, Python, Scratch

There are ~n~ cities and ~m~ roads between them. Your task is to process ~q~ queries where you have to determine the length of the shortest route between two given cities.

Input

  • The first input line has three integers ~n~, ~m~ and ~q~: the number of cities, roads, and queries.

Then, there are ~m~ lines describing the roads. Each line has three integers ~a~, ~b~ and ~c~: there is a road between cities ~a~ and ~b~ whose length is ~c~. All roads are two-way roads.

Finally, there are ~q~ lines describing the queries. Each line has two integers ~a~ and ~b~: determine the length of the shortest route between cities ~a~ and ~b~.

Output

  • Print the length of the shortest route for each query. If there is no route, print ~-1~ instead.

Constraints

  • ~1 \le n \le 500~
  • ~1 \le m \le n^2~
  • ~1 \le q \le 10^5~
  • ~1 \le a,b \le n~
  • ~1 \le c \le 10^9~

Example Input

4 3 5
1 2 5
1 3 9
2 3 3
1 2
2 1
1 3
1 4
3 2

Example Output

5
5
8
-1
3

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