Codeforces（E. Sleeping Schedule）DP

E know the game when the title is a DP. . . But did not make it. . .
Every DP do question the biggest problem is not knowing how to set up the array to represent a

DP is provided a [i] [j]
denotes the greatest benefit when the i-th value of j sleep period
then
if (j + a [i]) % h ~ R & lt between L
DP [i] [(j + a [i])% h ] = max (dp [i] [(j + a [i])% h], d [i-1] [j] + 1)
if not
dp [i] [(j + a [i])% h ] = max% h (d [i] [(j + a [i])], 0, d [i - 1] [j])

Code:

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int a[2005],inf=99999999;
int d[2005][2005];
void init()
{
    for(int i=0;i<2002;i++)
    {
        for(int j=0;j<2002;j++)
        {d[i][j]=-1;}
    }
}
int main()
{
    int n,h,l,r;
    cin>>n>>h>>l>>r;
    for(int i=1;i<=n;i++)
    {cin>>a[i];}
    init();//初始化f数组
    if(a[1]>=l&&a[1]<=r)
    {d[1][a[1]]=1;}
    else
    {d[1][a[1]]=0;}
    if(a[1]-1>=l&&a[1]-1<=r)
    {d[1][a[1]-1]=1;}
    else
    {d[1][a[1]-1]=0;}
    for(int i=2;i<=n;i++)
    {
        for(int j=0;j<=h;j++)
        {
            int op=a[i];
            if(d[i-1][j]!=-1)
            {
                int u=(j+op)%h;
                if(u>=l&&u<=r)
                {d[i][u]=max(d[i][u],d[i-1][j]+1);}
                else
                {d[i][u]=max(d[i][u],0);
                d[i][u]=max(d[i][u],d[i-1][j]);}
                op--;
                u=(j+op)%h;
                if(u>=l&&u<=r)
                {d[i][u]=max(d[i][u],d[i-1][j]+1);}
                else
                {d[i][u]=max(d[i][u],0);
                d[i][u]=max(d[i][u],d[i-1][j]);}
            }
        }
    }
    int maxx=-1;
    for(int j=0;j<=h;j++)
    {maxx=max(maxx,d[n][j]);}
    cout<<maxx<<endl;
    return 0;
}