Codeforces Round #421 (Div. 2)

A题

分析：开始从v0开始，每天增加a，然后超过v1就从v1开始

#include "iostream"
#include "cstdio"
#include "cstring"
#include "string"
using namespace std;
int c,v0,v1,a,l;
int main()
{
    cin>>c>>v0>>v1>>a>>l;
    if(c==0){
        cout<<"0"<<endl;
    }else{
        c=max(0,c-v0);
        int k=1;
        while(c>0){
            c+=l; v0=min(v0+a,v1);
            c-=v0; k++;
        }
        cout<<k<<endl;
    }
    return 0;
}

B题

分析：先求出正n变形的每个内角多少度，然后在把这个角分成n-2份，依次看取其中几份的时候绝对值的差最小即可

#include "iostream"
#include "cstdio"
#include "cstring"
#include "string"
#include "cmath"
#define eps 1e-9
using namespace std;
const double INF=200.0;
double n,B;
int main()
{
    cin>>n>>B;
    int num=n-2;
    int k;
    double ans=INF;
    double tt=(double)((n-2)*180.0/(double)n);
    tt/=num;
    for(int i=1;i<=num;i++){
        double res=tt*(double)i;
        if(fabs(res-(double)B)<ans){
            ans=fabs(res-(double)B);
            k=i+2;
        }
    }
    cout<<"2 "<<"1 "<<k<<endl;
    return 0;
}