#include<iostream>
using namespace std;
int a[105];
int main(){
    int n,D;
    cin>>n>>D;
    for(int i = 0;i < n;i++) cin>>a[i];
    int stock = a[0],profit = 0,last_sell = 0,having = 1;
    for(int i = 1;i < n;i++)
    {
        if(a[i] >= stock + D && having == 1)
        {
            profit += a[i] - stock;
            last_sell = stock;
            having = 0;
        }
        if(a[i] <= stock - D && having == 0)
        {
            stock = a[i];
            having = 1;
        }
    }
    cout<<profit;
} 

        if(a[i] >= stock + D && having == 1)
        {
            profit += a[i] - stock;
            last_sell = stock;
            having = 0;
        }

這裡也要加一個 stock = a[i];