HDU 4283 (第k个出场 区间DP)

http://blog.csdn.net/acm_cxlove/article/details/7964594

http://www.tuicool.com/articles/jyaQ7n

http://blog.csdn.net/woshi250hua/article/details/7973824

记忆化搜索(15MS)：

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <stack>
#include <queue>
#include <cctype>
#include <vector>
#include <iterator>
#include <set>
#include <map>
#include <sstream>
using namespace std;

#define mem(a,b) memset(a,b,sizeof(a))
#define pf printf
#define sf scanf
#define spf sprintf
#define pb push_back
#define debug printf("!\n")
#define INF 10000
#define MAX(a,b) a>b?a:b
#define blank pf("\n")
#define LL long long
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
#define pqueue priority_queue

const int MAXN =  + ;

int n,m;

int dp[][];
int a[],sum[];

int solve(int i,int j)
{
    int& ans = dp[i][j];
    if(ans!=-) return ans;
    if(i>=j) return ;
    ans = <<;
    for(int k = ;k<=j-i+;k++)
    {
        ans = min(ans,solve(i+,i+k-)+solve(i+k,j) + (k-)*a[i] + (sum[j]-sum[i+k-])*k);
    }
    return ans;
}

int main()
{
    int i,j;
    int t;
    cin>>t;
    while(t--)
    {
        cin>>n;
        sum[]=;
        for(i=;i<=n;i++)
        {
            sf("%d",&a[i]);
            sum[i]=sum[i-]+a[i];
        }
        mem(dp,-);
        pf("%d\n",solve(,n));
    }
    return ;
}

递推：

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <stack>
#include <queue>
#include <cctype>
#include <vector>
#include <iterator>
#include <set>
#include <map>
#include <sstream>
using namespace std;

#define mem(a,b) memset(a,b,sizeof(a))
#define pf printf
#define sf scanf
#define spf sprintf
#define pb push_back
#define debug printf("!\n")
#define INF 10000
#define MAX(a,b) a>b?a:b
#define blank pf("\n")
#define LL long long
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
#define pqueue priority_queue

const int MAXN =  + ;

int n,m;

int dp[][];
int a[],sum[];

int main()
{
    int i,j;
    int t;
    cin>>t;
    while(t--)
    {
        cin>>n;
        sum[]=;
        for(i=;i<=n;i++)
        {
            sf("%d",&a[i]);
            sum[i]=sum[i-]+a[i];
        }
        mem(dp,);
        for(int l = ;l<=n;l++)
        {
            for(i=;i<=n-l+;i++)
            {
                j = i+l-;
                dp[i][j] = <<;
                for(int k = ;k<=l;k++)
                {
                    dp[i][j] = min(dp[i][j],dp[i+][i+k-] + dp[i+k][j] + (k-)*a[i] + (sum[j]-sum[i+k-])*k);
                }
            }
        }
        pf("%d\n",dp[][n]);

    }
    return ;
}