×

计蒜客

  1. 题库
  2. Our Journey of Dalian Ends
  3. 问答
  • 26.65%
  • 4000ms
  • 131072K

Life is a journey, and the road we travel has twists and turns, which sometimes lead us to unexpected places and unexpected people.

Now our journey of Dalian ends. To be carefully considered are the following questions.

Next month in Xian, an essential lesson which we must be present had been scheduled.

But before the lesson, we need to attend a wedding in Shanghai.

We are not willing to pass through a city twice.

All available expressways between cities are known.

What we require is the shortest path, from Dalian to Xian, passing through Shanghai.

Here we go.

Input Format

There are several test cases.

The first line of input contains an integer $t$ which is the total number of test cases.

For each test case, the first line contains an integer $m~(m\le 10000)$ which is the number of known expressways.

Each of the following $m$ lines describes an expressway which contains two string indicating the names of two cities and an integer indicating the length of the expressway.

The expressway connects two given cities and it is bidirectional.

Output Format

For eact test case, output the shortest path from Dalian to Xian, passing through Shanghai, or output $-1$ if it does not exist.

样例输入1

0

样例输出1

3
2
Dalian Shanghai 3
Shanghai Xian 4
5
Dalian Shanghai 7
Shanghai Nanjing 1
Dalian Nanjing 3
Nanjing Xian 5
Shanghai Xian 8
3
Dalian Nanjing 6
Shanghai Nanjing 7
Nanjing Xian 8

样例解释1
7 12 -1

样例输入2

0

样例输出2


                            

样例输入3

0

样例输出3


                            

题目来源

2017 ACM-ICPC 亚洲区(乌鲁木齐赛区)网络赛

想挑战这道题吗

  • main.c