4.1个人赛

A - Balloons

 CodeForces - 998A 

题意就是：找到一分界点，前后两部分和不相同

#include<iostream>
using namespace std;
#define ll long long
#define N 107
int main()
{
ll a[N],d,sum=2;
int n;
cin>>n>>d;
for(int i=1;i<=n;i++)
cin>>a[i];
for(int i=1;i<n;i++){
if((a[i]+d)<(a[i+1]-d))
sum+=2;
else if((a[i]+d)==(a[i+1]-d))
sum+=1;
}
cout<<sum<<endl;
}

D - Sonya and Hotels

 CodeForces - 1004A

题意就是：找到一种点，前边点加d小于等于后面点减d再加两头的

#include<iostream>

using namespace std;

#define ll long long

#define N 107

int main() {

ll a[N],d,sum=2;

int n; cin>>n>>d;

for(int i=1;i<=n;i++) cin>>a[i];

for(int i=1;i<n;i++){

if((a[i]+d)<(a[i+1]-d)) sum+=2;

else if((a[i]+d)==(a[i+1]-d)) sum+=1; }

cout<<sum<<endl; }