P2032 「Poetize9」升降梯上

 1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cmath>
 4 #include<cstring>
 5 #include<algorithm>
 6 #include<iostream>
 7 #include<vector>
 8 #include<map>
 9 #include<set>
10 #include<queue>
11 #include<string>
12 #define inf 1000000000
13 #define maxn 2000
14 #define maxm 100
15 #define eps 1e-10
16 #define ll long long
17 #define pa pair<int,int>
18 #define for0(i,n) for(int i=0;i<=(n);i++)
19 #define for1(i,n) for(int i=1;i<=(n);i++)
20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
22 #define mod 1000000007
23 using namespace std;
24 inline int read()
25 {
26     int x=0,f=1;char ch=getchar();
27     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
28     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
29     return x*f;
30 }
31 int n,m,p,a[maxn],f[maxn][maxm];
32 int main()
33 {
34     freopen("input.txt","r",stdin);
35     freopen("output.txt","w",stdout);
36     n=read();m=read();
37     for1(i,m)a[i]=read();
38     for1(i,n)for1(j,m)f[i][j]=inf;
39     for1(i,m)if(!a[i])p=i;
40     for1(i,m)f[1][i]=abs(i-p);
41     bool flag=1;
42     while(flag)
43     {
44         flag=0;
45         for3(i,n,1) 
46          for1(j,m)
47           {
48               int k=i-a[j];
49              if(k>n||k<1)continue;
50              for1(l,m)
51               if(f[k][l]+abs(l-j)+abs(a[j])*2<f[i][j])flag=1,f[i][j]=f[k][l]+abs(l-j)+abs(a[j])*2;
52           }
53         //for1(i,n)for1(j,m)cout<<i<<‘ ‘<<j<<‘ ‘<<f[i][j]<<endl;
54     }
55     int ans=inf;
56     for1(i,m)ans=min(ans,f[n][i]);
57     printf("%d\n",ans>=inf/2?-1:ans);
58     return 0;
59 }