1 #include <bits/stdc++.h> 2 #define maxn 13003 3 #define _for(i,a,b) for(int i = (a);i < b;i ++) 4 typedef long long ll; 5 using namespace std; 6 inline ll read() 7 { 8 ll ans = 0; 9 char ch = getchar(), last = ' '; 10 while(!isdigit(ch)) last = ch, ch = getchar(); 11 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar(); 12 if(last == '-') ans = -ans; 13 return ans; 14 } 15 inline void write(ll x) 16 { 17 if(x < 0) x = -x, putchar('-'); 18 if(x >= 10) write(x / 10); 19 putchar(x % 10 + '0'); 20 } 21 int n,m; 22 int ap[203][203]; 23 int dp[203][203]; 24 25 int main() 26 { 27 n = read(), m = read(); 28 memset(dp,0,sizeof(dp)); 29 _for(i,0,n) 30 _for(j,0,m) 31 ap[i][j] = read(); 32 33 _for(i,0,m) 34 { 35 if(i>=m/2-1 && i<=m/2+1) 36 dp[n-1][i] = ap[n-1][i]; 37 else 38 dp[n-1][i] = -1000000; 39 } 40 41 for(int i = n-2;i >= 0;i --) 42 { 43 for(int j = 0;j < m;j ++) 44 { 45 if(j>=1) 46 dp[i][j] = dp[i+1][j-1]+ap[i][j]; 47 dp[i][j] = max(dp[i][j],dp[i+1][j]+ap[i][j]); 48 if(j<=m-2) 49 dp[i][j] = max(dp[i][j],dp[i+1][j+1]+ap[i][j]); 50 } 51 } 52 53 int rnt = 0; 54 _for(i,0,m) 55 rnt = max(rnt,dp[0][i]); 56 write(rnt); 57 return 0; 58 }