Problem10081--ABC345 —— F - Many Lamps

10081: ABC345 —— F - Many Lamps

[Creator : ]
Time Limit : 1.000 sec  Memory Limit : 512 MiB

Description

There is a simple graph with $N$ vertices numbered $1$ to $N$ and $M$ edges numbered $1$ to $M$. Edge $i$ connects vertices $u_i$ and $v_i$.  
Each vertex has one lamp on it. Initially, all the lamps are off.

Determine whether it is possible to turn exactly $K$ lamps on by performing the following operation between $0$ and $M$ times, inclusive.

-   Choose one edge. Let $u$ and $v$ be the endpoints of the edge. Toggle the states of the lamps on $u$ and $v$. That is, if the lamp is on, turn it off, and vice versa.

If it is possible to turn exactly $K$ lamps on, print a sequence of operations that achieves this state.

Input

The input is given from Standard Input in the following format:

```
$N$ $M$ $K$
$u_1$ $v_1$
$u_2$ $v_2$
$\vdots$
$u_M$ $v_M$
```

Output

If it is impossible to turn exactly $K$ lamps on, print `No`.  
Otherwise, first print `Yes`, and then print a sequence of operations in the following format:

```
$X$
$e_1$ $e_2$ $\dots$ $e_X$
```

Here, $X$ is the number of operations, and $e_i$ is the number of the edge chosen in the $i$-th operation. These must satisfy the following:

-   $0 \leq X \leq M$
-   $1 \leq e_i \leq M$

If multiple sequences of operations satisfy the conditions, any of them will be considered correct.

Constraints

-   $1 \leq N \leq 2 \times 10^5$
-   $0 \leq M \leq \min\left( 2 \times 10^5, \frac{N(N-1)}{2} \right)$
-   $0 \leq K \leq N$
-   $1 \leq u_i <v_i \leq N$
-   The given graph is simple.
-   All input values are integers.

Sample 1 Input

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

Sample 1 Output

Yes
3
3 4 5
If we operate according to the sample output, it will go as follows:
  • Choose edge 3. Turn on the lamps on vertex 2 and vertex 4.
  • Choose edge 4. Turn on the lamps on vertex 3 and vertex 5.
  • Choose edge 5. Turn on the lamp on vertex 1 and turn off the lamp on vertex 5.
After completing all operations, the lamps on vertices 1, 2, 3, and 4 are on. Therefore, this sequence of operations satisfies the conditions.
Other possible sequences of operations that satisfy the conditions include $X=4,(e_1,e_2,e_3,e_4)=(3,4,3,1)$. (It is allowed to choose the same edge more than once.)

Sample 2 Input

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

Sample 2 Output

No

Sample 3 Input

10 10 6
2 5
2 6
3 5
3 8
4 6
4 8
5 9
6 7
6 10
7 9

Sample 3 Output

Yes
3
10 9 6

Source/Category