【DP】hdu 2845

先對從左至右對每一行進行dp，再類似地從上到下dp，兩次dp！

#include <vector>#include <list>#include <map>#include <set>#include <queue>#include <string>#include <deque>#include <stack>#include <algorithm>#include <iostream>#include <iomanip>#include <cstdio>#include <cmath>#include <cstdlib>#include <limits.h>#include <time.h>#include <string.h>using namespace std;int lowbit(int t){return t&(-t);}int countbit(int t){return (t==0)?0:(1+countbit(t&(t-1)));}int gcd(int a,int b){return (b==0)?a:gcd(b,a%b);}#define LL long long#define PI acos(-1.0)#define N  200001#define Max INT_MAX#define Min INT_MIN#define eps 1e-8#define FRE freopen("a.txt","r",stdin)int dp1[N],b[N],dp2[N];int main(){    int n,m;    while(scanf("%d%d",&n,&m)!=EOF){        int i,j,k;        for(i=1;i<=n;i++){            for(j=1;j<=m;j++){                int a;                scanf("%d",&a);                dp1[0]=0;                if(j==1)dp1[j]=a;                else{                    dp1[j]=max(dp1[j-1], dp1[j-2]+a);                }            }            b[i]=dp1[m];        }        dp2[1]=b[1];        dp2[0]=0;        for(i=2;i<=n;i++)        dp2[i]=max(dp2[i-1],dp2[i-2]+b[i]);        printf("%d\n",dp2[n]);    }    return 0;}