| Given a non-empty tree with root R, and with weight Wi assigned to each tree node Ti. The weight of a path from R to L is defined to be the sum of the weights of all the nodes along the path from R to any leaf node L. Now given any weighted tree, you are supposed to find all the paths with their weights equal to a given number. For example, let's consider the tree showed in the following figure: for each node, the upper number is the node ID which is a two-digit number, and the lower number is the weight of that node. Suppose that the given number is 24, then there exists 4 different paths which have the same given weight: {10 5 2 7}, {10 4 10}, {10 3 3 6 2} and {10 3 3 6 2}, which correspond to the red edges in the figure.
Input Specification:Each input file contains one test case. Each case starts with a line containing 0 where For each test case, print all the paths with weight S in non-increasing order. Each path occupies a line with printed weights from the root to the leaf in order. All the numbers must be separated by a space with no extra space at the end of the line. Note: sequence {A1,A2,⋯,An} is said to be greater than sequence {B1,B2,⋯,Bm} if there exists 1≤k |
- 20 9 24
- 10 2 4 3 5 10 2 18 9 7 2 2 1 3 12 1 8 6 2 2
- 00 4 01 02 03 04
- 02 1 05
- 04 2 06 07
- 03 3 11 12 13
- 06 1 09
- 07 2 08 10
- 16 1 15
- 13 3 14 16 17
- 17 2 18 19
- 10 5 2 7
- 10 4 10
- 10 3 3 6 2
- 10 3 3 6 2
题目大意
给你树的路径和权值,请找出找从根结点到叶⼦结点路径上的权值相加之和等于Key的路径,并且从⼤到⼩输出路径
思路
DFS暴力遍历即可
- #include
- using namespace std;
- void DFS(int now,int sum);
- vector
int>> result; - vector<int> child[10001],op;
- int power[10001],N,M,key,a,b,c;
- bool cmp(vector<int>& x,vector<int>& y){
- for(int z=0;z<min(x.size(),y.size());z++){
- if(power[x[z]]!=power[y[z]]) return power[x[z]] > power[y[z]];
- }
- return false;
- }
- int main()
- {
- cin >> N >> M >> key;
- for(int z=0;z
> power[z]; - while (M--){
- cin >> a >> b;
- while (b--){
- cin >> c;
- child[a].push_back(c);
- }
- }
- DFS(0,power[0]);
- if(result.size()>1) sort(result.begin(),result.end(),cmp);
- for(const auto& x:result){
- cout << power[0];
- for(int y:x) cout << " " << power[y];
- putchar('\n');
- }
- return 0;
- }
- void DFS(int now,int sum)
- {
- if(child[now].empty()){
- if(sum==key) result.push_back(op);
- return;
- }else{
- for(int x:child[now]) {
- op.push_back(x);
- DFS(x,sum+power[x]);
- op.pop_back();
- }
- }
- }
