dp[ i ][ j ]状态代表必须要从左走到右,再从右走到左,然后i——j所有村庄救完。
#include"bits/stdc++.h"
using namespace std;
typedef long long ll;
const int MX = 3003;
const ll INFLL = 0x3f3f3f3f3f3f3f3f;
int n;
ll dp[MX][MX],f[MX],s[MX];
ll a[MX];
int main()
{
#ifdef LOCAL
freopen("input.txt","r",stdin);
#else
freopen("ebola.in","r",stdin);
freopen("ebola.out","w",stdout);
#endif // LOCAL
while(~scanf("%d",&n) && n) {
for(int i = 1; i <= n; i++)
scanf("%d",&a[i]);
s[n+1] = 0;
for(int i = n; i >= 1; i--)
s[i] = s[i+1]+a[i];
for(int j = 1; j <= n; j++) {
dp[j][j] = s[j+1];
for(int i = j-1; i >= 1; i--) {
dp[i][j] = dp[i+1][j] + s[i+1] + s[j+1] + min(s[i+1], (ll)s[j+1] + a[i]*(j-i)*3 );
}
}
for(int j = 1; j <= n; j++) {
f[j] = INFLL;
for(int i = 0; i < j; i++) {
f[j] = min(f[j], f[i] + dp[i+1][j] + s[j+1]*(j-i));
}
}
printf("%lld\n",f[n]);
}
return 0;
}