Codevs3002 stones merge 3, codevs3002 stones merge

Codevs3002 stones merge 3, codevs3002 stones merge
DescriptionDescription

There are n piles of stones in a column, each pile of stones has a weight w [I], each merge can combine adjacent two piles of stones, the cost of one merge is the weight of two piles of stones and w [I] + w [I + 1]. Ask how to arrange the merge sequence to minimize the total merge cost.

Input description Input Description

The first line is an integer n (n <= 3000)

N integers w1, w2. .. wn (wi <= 3000) in the second row)

Output description Output Description

An integer indicates the minimum merge cost.

Sample Input Sample Input

4

4 1 1 4

Sample output Sample Output

18

Data range and prompt Data Size & Hint

The data range is extended compared to the "Stone merge"

 

Nothing to say,

Is the Quadrilateral inequality optimization.

Prove that neither will I

Drop a blog Link

 

http://blog.csdn.net/noiau/article/details/72514812

 

 

#include<cstdio>#include<cstring>const int MAXN=1e5+10,INF=1e8+10;using namespace std;inline char nc(){    static char buf[MAXN],*p1=buf,*p2=buf;    return p1==p2&&(p2=(p1=buf)+fread(buf,1,MAXN,stdin)),p1==p2?EOF:*p1++;}inline int read(){    char c=nc();int x=0,f=1;    while(c<'0'||c>'9'){if(c=='-')f=-1;c=nc();}    while(c>='0'&&c<='9'){x=x*10+c-'0';c=nc();}    return x*f;}int dp[3001][3001],sum[MAXN],s[3001][3001];int main(){    #ifdef WIN32    freopen("a.in","r",stdin);    #else    #endif    int N=read();    for(int i=1;i<=N;i++) sum[i]=read(),sum[i]+=sum[i-1],s[i][i]=i;    for(int i=N;i>=1;i--)     {        for(int j=i+1;j<=N;j++)        {            int mn=INF,mnpos=0;            for(int k=s[i][j-1];k<=s[i+1][j];k++)            {                if(dp[i][k]+dp[k+1][j]+sum[j]-sum[i-1] < mn)                {                    mn=dp[i][k]+dp[k+1][j]+sum[j]-sum[i-1];                    mnpos=k;                }            }            dp[i][j]=mn;            s[i][j]=mnpos;        }    }     printf("%d",dp[1][N]);    return 0;}