POJ 3262 protecting the Flowers "greed"

The beginning is always wrong, do not know how, and later found that the first sum on the assignment to zero, and then minus is definitely negative, a start sum did not addend, want to leak, suddenly no words, wrote dozens of days, today just solve, hey ~ ~ Note the output may be more than the integer type

http://blog.csdn.net/u014004096/article/details/36876287

Protecting the Flowers

Time Limit: 2000MS		Memory Limit: 65536K
Total Submissions: 4604		Accepted: 1838

Description

Farmer John went to cut some wood and left N (2≤ n ≤100,000) cows eating the grass, as usual. When he returned, he found-to-his horror, the cluster of cows is in his garden eating his beautiful flowers. Wanting to minimize the subsequent damage, FJ decided to take immediate action and transport each cow back to its own barn .

Each cow I was at a location, that's ti minutes (1≤ ti ≤2,000,000) away from its own barn. Furthermore, while waiting for transport, she destroys di (1≤ di ≤100) flowers per minute. No matter how hard he tries, FJ can only transport one cow at a time back to her barn. Moving Cow i to their barn requires 2x ti minutes (ti to get there and ti to return). FJ starts at the flower patch, transports the cow to it barn, and then walks back to the flowers, taking no extra time to Get to the next cow that needs transport.

Write a program to determine the order in which FJ should pick up the cows so and the total number of flowers destroyed I s minimized.

Input

Line 1: A single integer N
Lines 2.. N+1:each line contains, space-separated integers, Tiand Di, that's describe a single cow ' s characteristics

Output

Line 1: A single integer So is the minimum number of destroyed flowers

Sample Input

63 12 52 33 24 11 6

Sample Output

86

Hint

FJ returns the cows in the following order:6, 2, 3, 4, 1, 5. While he's transporting cow 6 to the barn, the others destr Oy flowers; Next he'll take Cow 2, losing to more about his beautiful flora. For the cows 3, 4, 1 he loses, and 6 flowers respectively. When he picks Cow 5 there was no more cows damaging the flowers, so the loss for that Cow is zero. The total flowers lost this to is 24 + 28 + 16 + 12 + 6 = 86.

Source

Usaco January Silver

POJ 3262 protecting the Flowers "greed"