河南第六届ACM省赛（探 寻 宝 藏）（双线程DP）

题目地址：http://acm.nyist.net/JudgeOnline/problem.php?pid=712

思路：比较裸的双线程DP吧

AC代码：

#include <iostream>#include <cstdio>#include <cstdlib>#include <algorithm>#include <queue>#include <stack>#include <map>#include <cstring>#include <climits>#include <cmath>#include <cctype>const int inf = 0x3f3f3f3f;//1061109567typedef long long LL;#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1using namespace std;int map1[55][55];int dp[55][55][55][55];int main(){    int t,m,n;    scanf("%d",&t);    while(t--)    {        scanf("%d%d",&m,&n);        memset(dp,0,sizeof(dp));        for(int i=1; i<=m; i++)        {            for(int j=1; j<=n; j++)            {                scanf("%d",&map1[i][j]);            }        }        for(int i=1; i<=m; i++)        {            for(int j=1; j<=n; j++)            {                for(int k=i+1; k<=m; k++)                {                    int l = i + j - k;                    if(l <= 0)                        break;                    dp[i][j][k][l] = max(max(dp[i-1][j][k-1][l],dp[i][j-1][k][l-1]),max(dp[i-1][j][k][l-1],dp[i][j-1][k-1][l]));                    dp[i][j][k][l] += map1[i][j] + map1[k][l];                }            }        }        printf("%d\n",dp[m-1][n][m][n-1]+map1[1][1]+map1[m][n]);    }    return 0;}

错误的三维的：

#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>using namespace std;int map1[55][55];int dp[110][55][55];int main(){    int m,n,t;    scanf("%d",&t);    while(t--)    {        scanf("%d%d",&m,&n);        memset(dp,0,sizeof(dp));        for(int i=0; i<m; i++)        {            for(int j=0; j<n; j++)            {                scanf("%d",&map1[i][j]);            }        }        int k;        for(k=1; k<m+n-2; k++)        {            for(int i=0; i<m; i++)            {                for(int j=0; j<n; j++)                {                    if(i==j)                        continue;                    dp[k][i][j] = max(max(dp[k-1][i][j],dp[k-1][i-1][j]),max(dp[k-1][i][j-1],dp[k-1][i-1][j-1]));                    dp[k][i][j] += map1[i][k-i] + map1[j][k-j];                }            }        }        printf("%d\n",dp[k-1][m-1][m-2]+map1[0][0]+map1[m-1][n-1]);    }    return 0;}