JZOJ 5838. 旅游路线 最大子段和

 1 #include <cstdio>
 2 #include <iostream>
 3 #include <cstring>
 4 #define N 207
 5 #define LL long long
 6 #define rep(i,a,b) for(int i=a;i<=b;i++)
 7 #define max(a,b) (a)>(b)?(a):(b)
 8 using namespace std;
 9 int n,m,val[N][N];
10 LL f[N], Q[N][N], ans;
11 
12 void Init(){
13     scanf("%d%d",&n,&m);
14     rep(i,1,n)
15         rep(j,1,m){
16             scanf("%d",&val[i][j]);
17             Q[i][j]=Q[i-1][j]+val[i][j];
18         }
19 }
20 
21 void Get(int up,int down){
22     rep(i,1,m)
23         f[i]=Q[down+up][i]-Q[up-1][i];
24     LL sum=0;
25     rep(i,1,m){
26         if(sum+f[i]>0)    sum+=f[i],ans=max(ans,sum);
27         else sum=0;
28     }
29         
30 }
31 
32 void Work(){
33     rep(i,1,n)
34         rep(j,0,n-i)
35             Get(i,j);
36 }
37 
38 int main(){
39     Init();
40     Work();
41     printf("%lld",ans);
42 }