TYVJ1264

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream>
 4 #include <algorithm>
 5 using namespace std;
 6 
 7 const int maxn = 8001;
 8 const int maxm = 1001;
 9 int a[maxn][maxm];
10 int main()
11 {
12     freopen("in.txt","r",stdin);
13     int n,m;
14     cin>>m>>n;
15     for(int i = 1;i<=n;++i)
16         for(int j = 1;j<=m;++j)
17             scanf("%d",&a[i][j]);
18     for(int i =  n-1;i>=1;--i)
19         for(int j = 1;j<=m;++j)if(a[i][j]!=-1)
20         {
21             if(j==1)a[i][j]+=max(a[i+1][j],a[i+1][j+1]);
22             else if(j==m)a[i][j]+=max(a[i+1][j],a[i+1][j-1]);
23             else a[i][j]+=max(a[i+1][j],max(a[i+1][j-1],a[i+1][j+1]));
24         }
25     int ans = -1;
26     for(int i = 1;i<=m;++i)
27         ans=max(ans,a[1][i]);
28     printf("%d\n",ans);
29 
30     return 0;
31 }