pat 1079 Total Sales of Supply Chain

最新推荐文章于 2023-06-15 13:52:54 发布

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本文介绍了一个供应链销售总额的计算方法，通过构建一个包含零售商、分销商和供应商的网络，使用递归深度优先搜索算法计算从根供应商到最终消费者的总销售额。

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

#include <iostream>
#include <cstdio>
#include <vector>
#include <map>
#include <utility>
using namespace std;

vector<vector<int> > vec(100010);
map<int, long long> leaf;
int n;
double p, r;
double sum = 0.0;

void dfs(int index, double price) {
	if(leaf.count(index) > 0) {
		sum += price * leaf[index];
		return;
	}

	for (int i = 0; i < vec[index].size(); ++i)
	{
		dfs(vec[index][i], price*(1+r/100.0));
	}
}

int main() {

	scanf("%d %lf %lf", &n, &p, &r);

	for (int i = 0; i < n; ++i)
	 {
	 	int tmp;
	 	scanf("%d", &tmp);

	 	if(tmp == 0) {
	 		long long x;
	 		scanf("%lld", &x);
	 		leaf[i]=x;
	 	}

	 	for(int j = 0; j < tmp; j++) {
	 		int x;
	 		scanf("%d", &x);
	 		vec[i].push_back(x);
	 	}
	 }

	 dfs(0, p);

	 printf("%.1lf\n", sum); 
	return 0;
}

要用 double 类型和 long long 类型，如果用 float 和int ，好几个测试点会通不过。