[USACO13MAR] The Cow Run G/S

Farmer John has forgotten to repair a hole in the fence on his farm, and his N cows (1 <= N <= 1,000) have escaped and gone on a rampage! Each minute a cow is outside the fence, she causes one dollar worth of damage. FJ must visit each cow to install a halter that will calm the cow and stop the damage. Fortunately, the cows are positioned at distinct locations along a straight line on a road outside the farm. FJ knows the location P\_i of each cow i (-500,000 <= P\_i <= 500,000, P\_i != 0) relative to the gate (position 0) where FJ starts. FJ moves at one unit of distance per minute and can install a halter instantly. Please determine the order that FJ should visit the cows so he can minimize the total cost of the damage; you should compute the minimum total damage cost in this case. 农夫约翰的牧场围栏上出现了一个洞，有 $N$（$1\le N\le 1000$）只牛从这个洞逃出了牧场。这些出逃的奶牛很狂躁，他们在外面到处搞破坏，每分钟每头牛都会给约翰带来 $1$ 美元的损失。约翰必须用缰绳套住所有的牛，以停止他们搞破坏。 幸运的是，奶牛们都在牧场外一条笔直的公路上，牧场的大门恰好位于公里的 $0$ 点处。约翰知道每头牛距离牧场大门的距离 $P_i$（$-5\times10^5\le P_i\le5\times 10^5$，$P_i\ne0$）。 约翰从农场大门出发，每分钟移动一个单位距离，每到一头牛所在的地点，约翰就会给它套上缰绳，套缰绳不花时间。按怎样的顺序去给牛套缰绳才能使约翰损失的费用最少？

\* Line 1: The number of cows, N. \* Lines 2..N+1: Line i+1 contains the integer P\_i.

\* Line 1: The minimum total cost of the damage.

4 
-2 
-12 
3 
7 

50 

Four cows placed in positions: -2, -12, 3, and 7. The optimal visit order is -2, 3, 7, -12. FJ arrives at position -2 in 2 minutes for a total of 2 dollars in damage for that cow. He then travels to position 3 (distance: 5) where the cumulative damage is 2 + 5 = 7 dollars for that cow. He spends 4 more minutes to get to 7 at a cost of 7 + 4 = 11 dollars for that cow. Finally, he spends 19 minutes to go to -12 with a cost of 11 + 19 = 30 dollars. The total damage is 2 + 7 + 11 + 30 = 50 dollars.