题解：AtCoder AT_awc0003_a Product Quality Evaluation

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【题目来源】

AtCoder：A - Product Quality Evaluation

【题目描述】

Takahashi is in charge of quality control at a factory. This factory manufacturesN NNtypes of products, each numbered from1 11toN NN.
高桥负责一家工厂的质量控制工作。这家工厂生产N NN种产品，每种产品编号从1 11到N NN。

Each product has two metrics: a “quality index” and a “production quantity.” The quality index of producti iiisA i A_iAi​, and its daily production quantity isB i B_iBi​units. A higher quality index indicates that defective items are more likely to occur.
每种产品有两个指标：“质量指数"和"生产数量”。产品i ii的质量指数为A i A_iAi​，其日生产数量为B i B_iBi​单位。质量指数越高，表明次品出现的可能性越大。

Takahashi decided to calculate a “risk score” for each product. The risk score of producti iiis defined as the product of the quality indexA i A_iAi​and the production quantityB i B_iBi​, namelyA i × B i A_i \times B_iAi​×Bi​. A higher risk score means that more attention is required for that product.
高桥决定为每种产品计算一个"风险分数"。产品i ii的风险分数定义为质量指数A i A_iAi​与生产数量B i B_iBi​的乘积，即A i × B i A_i × B_iAi​×Bi​。风险分数越高，意味着该产品需要更多关注。

Takahashi believes that products with a risk score ofK KKor higher need to be prioritized for improvement. Find the number of products whose risk score isK KKor higher.
高桥认为，风险分数为K KK或更高的产品需要优先进行改进。求风险分数为K KK或更高的产品数量。

【输入】

N NNK KK
A 1 A_1A1​B 1 B_1B1​
A 2 A_2A2​B 2 B_2B2​
⋮ \vdots⋮
A N A_NAN​B N B_NBN​

• The first line contains an integerN NNrepresenting the number of product types and an integerK KKrepresenting the risk score threshold, separated by a space.
• From the 2nd line to the( N + 1 ) (N+1)(N+1)-th line, information about each product is given.
• The( i + 1 ) (i+1)(i+1)-th line( 1 ≤ i ≤ N ) (1 \leq i \leq N)(1≤i≤N)contains the quality indexA i A_iAi​and the production quantityB i B_iBi​of producti ii, separated by a space.

【输出】

Output the number of products whose risk score isK KKor higher, in a single line.

【输入样例】

3 100 10 5 20 10 5 30

【输出样例】

2

【解题思路】

【算法标签】

#模拟#

【代码详解】

#include<bits/stdc++.h>usingnamespacestd;#defineintlonglongintn,k,ans;// n: 商品数量，k: 目标金额，ans: 计数signedmain(){cin>>n>>k;// 读入商品数量和目标金额for(inti=1;i<=n;i++){inta,b;// a: 单价，b: 数量cin>>a>>b;// 读入单价和数量if(a*b>=k)// 如果总价大于等于目标金额k{ans++;// 计数器加1}}cout<<ans<<endl;// 输出满足条件的商品数量return0;}

【运行结果】

3 100 10 5 20 10 5 30 2