NOIP2005 过河

#include<iostream>
#include<cstdio>
#include<algorithm>
#define maxint 105
#define maxn 700005
using namespace std;
int l,s,t,m,nl;
int dp[maxn],stone[maxn],vis[maxn],ans;
bool cmp(int a,int b){
    return a<b;
}
int main(){
    cin>>l>>s>>t>>m;
    int tmp,next,last = 0,cut = 0;
    for(int i = 1;i <= m;i++){
        scanf("%d",&tmp);
        stone[i] = tmp;
    }
    sort(stone+1,stone+1+m,cmp);
    stone[m+1] = l;
    for(int i = 1;i <= m+1;i++){
        tmp = stone[i];
        tmp -= cut;
        int river = tmp - last - 1;
        int rec = river;
        river %= 11007;
        tmp = last+river+1;
        vis[tmp] = 1;
        last = tmp;
        if(i == m+1) l = tmp;
    }
    for(int i = 1;i <= l;i++){
        dp[i] = maxint;
    }
    ans = maxint;
    for(int i = 0;i < l;i++){
        if(vis[i]){
            dp[i]++;
        }
        for(int j = s;j <= t;j++){
            if(i+j>=l){
                ans = min(ans,dp[i]);
                break;
            }
            dp[i+j] = dp[i+j] > dp[i] ? dp[i] : dp[i+j];
            
        }
    }
    cout<<ans;
    return 0;
}