题解归档 - cf104118A

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• 本地编号：cf104118A
• 本地来源：problems/cf104118A/idea.md
• 题目链接：https://codeforces.com/gym/104118/problem/A
• 原始标题：cf104118A - An Easy Calculus Question

思路

cf104118A - An Easy Calculus Question

The full statement is in contests/104118/statements.pdf because the HTML page only contains samples.

Use the constants given by the statement hint:

• a=-2, b=1, c=-14, d=17.

Then evaluate the piecewise function:

• x <= -3: -(x+4)^2+8
• -3 < x <= 2: -2x+1
• x > 2: x^3-14x+17

Input x is an integer in [-10,10], and the answer is always integer.

代码

来源：problems/cf104118A/solution.cpp

#include<bits/stdc++.h>
using namespace std;
using ll=long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    ll x;
    cin>>x;
    ll ans;
    if(x<=-3) ans=-(x+4)*(x+4)+8;
    else if(x<=2) ans=-2*x+1;
    else ans=x*x*x-14*x+17;
    cout<<ans<<"\n";
    return 0;
}