# PAT A1079

``` 思路借鉴了之前的图的层数，发现这个贼好用；关键在于输出浮点数的格式，这个要注意一下 #include<iostream> #include<stdlib.h> #include<stdio.h> #include<vector> #include<queue> #include<math.h> using namespace std; using std::vector; using std::queue; const int maxn=100010; struct node{ double data; vector<int>child; int layer=0; }Node[maxn]; int n; double p,r; vector<int>leaf; void BFS(int x){ int layer=0; queue<int>q; q.push(x); while(!q.empty()){ layer++; int index; int length=q.size(); for(int i=0;i<length;i++){ index=q.front(); q.pop(); Node[index].layer=layer; for(int j=0;j<Node[index].child.size();j++){ q.push(Node[index].child[j]); } } } } int main(){ int num; scanf("%d%lf%lf",&n,&p,&r); for(int i=0;i<n;i++){ scanf("%d",&num); if(num==0){ scanf("%lf",&Node[i].data); leaf.push_back(i); }else{ for(int j=0;j<num;j++){ int child; scanf("%d",&child); Node[i].child.push_back(child); } } } BFS(0); double sum; for(int i=0;i<leaf.size();i++){ sum+=pow(1+r/100,Node[leaf[i]].layer-1)*Node[leaf[i]].data; } printf("%.1fn",sum*p); system("pause"); return 0; } ```