pat1079. Total Sales of Supply Chain (25)

1079. Total Sales of Supply Chain (25)

时间限制

250 ms

内存限制

65536 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

A supply chain is a network of retailers（零售商）, distributors（经销商）, and suppliers（供应商）-- everyone involved in moving a product from supplier to customer.

Starting from one root supplier, everyone on the chain buys products from one's supplier in a price P and sell or distribute them in a price that is r% higher than P. Only the retailers will face the customers. It is assumed that each member in the supply chain has exactly one supplier except the root supplier, and there is no supply cycle.

Now given a supply chain, you are supposed to tell the total sales from all the retailers.

Input Specification:

Each input file contains one test case. For each case, the first line contains three positive numbers: N (<=10⁵), the total number of the members in the supply chain (and hence their ID's are numbered from 0 to N-1, and the root supplier's ID is 0); P, the unit price given by the root supplier; and r, the percentage rate of price increment for each distributor or retailer. Then N lines follow, each describes a distributor or retailer in the following format:

K_i ID[1] ID[2] ... ID[K_i]

where in the i-th line, K_i is the total number of distributors or retailers who receive products from supplier i, and is then followed by the ID's of these distributors or retailers. K_j being 0 means that the j-th member is a retailer, then instead the total amount of the product will be given after K_j. All the numbers in a line are separated by a space.

Output Specification:

For each test case, print in one line the total sales we can expect from all the retailers, accurate up to 1 decimal place. It is guaranteed that the number will not exceed 10¹⁰.

Sample Input:

10 1.80 1.00
3 2 3 5
1 9
1 4
1 7
0 7
2 6 1
1 8
0 9
0 4
0 3

Sample Output:

42.4

---

提交代码

BFS。由于数量是long long级别，用DFS会段错误。

 #include<cstdio>
 #include<algorithm>
 #include<iostream>
 #include<stack>
 #include<vector>
 #include<set>
 #include<map>
 #include<queue>
 using namespace std;
 map<long long,vector<long long> > edge;
 map<long long,long long> re;
 int main(){
     //freopen("D:\\INPUT.txt","r",stdin);
     long long n,i,num,v;
     double price,r,total=;
     scanf("%lld %lf %lf",&n,&price,&r);
     for(i=;i<n;i++){
         scanf("%lld",&num);
         if(!num){
             scanf("%lld",&re[i]);
             continue;
         }
         while(num){
             scanf("%lld",&v);
             edge[i].push_back(v);
             num--;
         }
     }
     queue<long long> q;
     q.push();
     long long cur;
     long long last,e=;
     //last记录当前层不为叶结点的节点
     if(re.count()){//root可能也会直接向顾客出售
         total+=price*re[];
         q.pop();
     }
     r=r/;
     price*=+r;//当前下一层向外卖的价格
     while(!q.empty()){
         cur=q.front();
         q.pop();
         for(i=;i<edge[cur].size();i++){
             if(re.count(edge[cur][i])){
                 total+=price*re[edge[cur][i]];
                 continue;
             }
             q.push(edge[cur][i]);
             last=edge[cur][i];
         }
         if(cur==e){
             e=last;
             price*=+r;
         }
     }
     printf("%.1lf\n",total);
     return ;
 }

断错误的DFS。

 #include<cstdio>
 #include<algorithm>
 #include<iostream>
 #include<stack>
 #include<vector>
 #include<set>
 #include<map>
 using namespace std;
 map<long long,vector<long long> > edge;
 map<long long,long long> re;
 map<long long,bool> vis;
 void DFS(long long num,double &total,double price,double r){
     vis[num]=true;
     long long i;
     if(!edge[num].size()){

         //cout<<num<<endl;

         total+=re[num]*price;
         return;
     }
     for(i=;i<edge[num].size();i++){
         if(!vis[edge[num][i]]){
             DFS(edge[num][i],total,price*(+r),r);
         }
     }
 }
 int main(){
     //freopen("D:\\INPUT.txt","r",stdin);
     long long n,i,num,v;
     double price,r,total=;
     scanf("%lld %lf %lf",&n,&price,&r);
     for(i=;i<n;i++){
         vis[i]=false;
         scanf("%lld",&num);
         if(!num){
             scanf("%lld",&re[i]);
             continue;
         }
         while(num){
             scanf("%lld",&v);
             edge[i].push_back(v);
             num--;
         }
     }
     DFS(,total,price,r/);
     printf("%.1lf\n",total);
     return ;
 }