Codeforces Testing Round 5
B
Dominoes
Codeforces
2000
原题
← AC →
翻译中…

You have a set of dominoes. Each domino is a rectangular tile with a line dividing its face into two square ends. Can you put all dominoes in a line one by one from left to right so that any two dominoes touch with the sides that had the same number of points? You can rotate the dominoes, changing the left and the right side (domino "1-4" turns into "4-1").

翻译中…

Input

翻译中…

The first line contains the number $*n*$ ($1 ≤ *n* ≤ 100$). Next $*n*$ lines contain the dominoes. Each of these lines contains two numbers — the number of points (spots) on the left and the right half, correspondingly. The numbers of points (spots) are non-negative integers from 0 to 6. Duplicates (identical tiles) may be present in the given set.

翻译中…

Output

翻译中…

Print "No solution", if it is impossible to arrange the dominoes in the required manner. If the solution exists, then describe any way to arrange the dominoes. You put the dominoes from left to right. In each of the $*n*$ lines print the index of the domino to put in the corresponding position and then, after a space, the character "+" (if you don't need to turn the domino) or "–" (if you need to turn it).

翻译中…

样例

Input #1
5
1 2
2 4
2 4
6 4
2 1
Output #1
2 -
1 -
5 -
3 +
4 -
InputCopy OutputCopy
题目信息
题号
267B
时间限制
1 s
内存限制
256 MB
标签
DFS 及类似
图论

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。