POJ 1651 Multiplication Puzzle

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 const int maxn = 105;
 6 const int inf = 0x3f3f3f3f;
 7 int num[maxn], dp[maxn][maxn];
 8 int n;
 9 
10 int dfs(int l, int r){
11     if (abs(l-r) < 2)
12         return 0;
13     if (r-l == 2)
14         return dp[l][r] = num[l]*num[l+1]*num[r];
15     if (dp[l][r] != inf)
16         return dp[l][r];
17     for (int i=l+1; i<r; ++i)
18         dp[l][r] = min(dp[l][r], dfs(l, i)+dfs(i, r)+num[l]*num[i]*num[r]);
19     return dp[l][r];
20 }
21 
22 int main(){
23     while (~scanf("%d", &n)){
24         for (int i=0; i<n; ++i)
25             scanf("%d", num+i);
26         memset(dp, inf, sizeof(dp));
27         dfs(0, n-1);
28         printf("%d\n", dp[0][n-1]);
29     }
30     return 0;
31 }