Poj 1651 multiplication puzzle

Portal @ Baidu

Multiplication puzzle

Time limit:1000 ms		Memory limit:65536 K

Description

The multiplication puzzle is played with a row of cards, each containing a single positive integer. during the move player takes one card out of the row and scores the number of points equal to the product of the number on the card taken and the numbers on the cards on the left and on right of it. it is not allowed to take out the first and the last card in the row. after the final move, only two cards are left in the row.

The goal is to take cards in such order as to minimize the total number of scored points.

For example, if cards in the row contain numbers 10 1 50 20 5, player might take a card with 1, then 20 and 50, scoring
10*1*50 + 50*20*5 + 10*50*5 = 500 + 5000 + 2500 = 8000
If he wocould take the cards in the opposite order, I. e. 50, then 20, then 1, the score wocould be
1*50*20 + 1*20*5 + 10*1*5 = 1000 + 100 + 50 = 1150.

Input

The first line of the input contains the number of cards N (3 <= n <= 100). The second line contains N integers in the range from 1 to 100, separated by spaces.

Output

Output must contain a single integer-the minimal score.

Sample Input

610 1 50 50 20 5

Sample output

3650

Source

Northeastern Europe 2001, far-Eastern subregion water DP

 1 #include<set> 2 #include<cstdio> 3 #include<cstdlib> 4 #include<cstring> 5 #include<iostream> 6 #include<algorithm> 7 using namespace std; 8 const int N = 110; 9 #define For(i,n) for(int i=1;i<=n;i++)10 #define Rep(i,l,r) for(int i=l;i<=r;i++)11 #define Down(i,r,l) for(int i=r;i>=l;i--)12 int n,A[N];13 long long dp[N][N];14 15 int main(){16     scanf("%d",&n);17     For(i,n) scanf("%d",&A[i]);18     For(i,n-2) dp[i][i+2]=A[i]*A[i+2]*A[i+1];19     Down(i,n-2,1)20       Rep(j,i+2,n)21         Rep(k,i+1,j-1)22           if(dp[i][j])23                 dp[i][j]=min(dp[i][j],dp[i][k]+dp[k][j]+A[i]*A[k]*A[j]);24           else  dp[i][j]=dp[i][k]+dp[k][j]+A[i]*A[k]*A[j];25     cout<<dp[1][n]<<endl;   26     return 0;27 }

 

Poj 1651 multiplication puzzle