Codeforces Round 364 (Div. 2)
F
Break Up
Codeforces
未评级
原题
← E→
翻译中…

Again, there are hard times in Berland! Many towns have such tensions that even civil war is possible.

翻译中…

There are $*n*$ towns in Reberland, some pairs of which connected by two-way roads. It is not guaranteed that it is possible to reach one town from any other town using these roads.

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Towns $*s*$ and $*t*$ announce the final break of any relationship and intend to rule out the possibility of moving between them by the roads. Now possibly it is needed to close several roads so that moving from $*s*$ to $*t*$ using roads becomes impossible. Each town agrees to spend money on closing no more than one road, therefore, the total number of closed roads will be no more than two.

翻译中…

Help them find set of no more than two roads such that there will be no way between $*s*$ and $*t*$ after closing these roads. For each road the budget required for its closure was estimated. Among all sets find such that the total budget for the closure of a set of roads is minimum.

翻译中…

Input

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The first line of the input contains two integers $*n*$ and $*m*$ ($2 ≤ *n* ≤ 1000$, $0 ≤ *m* ≤ 30 000$) — the number of towns in Berland and the number of roads.

翻译中…

The second line contains integers $*s*$ and $*t*$ ($1 ≤ *s*, *t* ≤ *n*$, $*s* ≠ *t*$) — indices of towns which break up the relationships.

翻译中…

Then follow $*m*$ lines, each of them contains three integers $*x*_{*i*}$, $*y*_{*i*}$ and $*w*_{*i*}$ ($1 ≤ *x*_{*i*}, *y*_{*i*} ≤ *n*$, $1 ≤ *w*_{*i*} ≤ 10^{9}$) — indices of towns connected by the $*i*$-th road, and the budget on its closure.

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All roads are bidirectional. It is allowed that the pair of towns is connected by more than one road. Roads that connect the city to itself are allowed.

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Output

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In the first line print the minimum budget required to break up the relations between $*s*$ and $*t*$, if it is allowed to close no more than two roads.

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In the second line print the value $*c*$ ($0 ≤ *c* ≤ 2$) — the number of roads to be closed in the found solution.

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In the third line print in any order $*c*$ diverse integers from $1$ to $*m*$ — indices of closed roads. Consider that the roads are numbered from $1$ to $*m*$ in the order they appear in the input.

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If it is impossible to make towns $*s*$ and $*t*$ disconnected by removing no more than $2$ roads, the output should contain a single line -1.

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If there are several possible answers, you may print any of them.

翻译中…

样例

Input #1
6 7
1 6
2 1 6
2 3 5
3 4 9
4 6 4
4 6 5
4 5 1
3 1 3
Output #1
8
2
2 7
InputCopy OutputCopy
Input #2
6 7
1 6
2 3 1
1 2 2
1 3 3
4 5 4
3 6 5
4 6 6
1 5 7
Output #2
9
2
4 5
InputCopy OutputCopy
Input #3
5 4
1 5
2 1 3
3 2 1
3 4 4
4 5 2
Output #3
1
1
2
InputCopy OutputCopy
Input #4
2 3
1 2
1 2 734458840
1 2 817380027
1 2 304764803
Output #4
-1
InputCopy OutputCopy
题目信息
题号
701F
时间限制
3 s
内存限制
256 MB

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。