1739 - [Usaco2005 mar]Space Elevator 太空电梯
The cows are going to space! They plan to achieve orbit by building a sort of space elevator: a giant tower of blocks. They have K (1 <= K <= 400) different types of blocks with which to build the tower. Each block of type i has height h_i (1 <= h_i <= 100) and is available in quantity c_i (1 <= c_i <= 10). Due to possible damage caused by cosmic rays, no part of a block of type i can exceed a maximum altitude a_i (1 <= a_i <= 40000). Help the cows build the tallest space elevator possible by stacking blocks on top of each other according to the rules. 牛们要到太空去了！他们打算建造一座太空电梯来送他们进入轨道． 有K(1≤K≤400)神方块，第i种有一个特定的高度hi(l≤hi≤100)，一定的存量ci(l≤ci≤10).为防宇宙射线的破坏，第i种方块的任何部分不能超过高度ai(l≤ai≤40000)． 请用这些方块堆出最高的太空电梯．
输入
Line 1: A single integer, K * Lines 2..K+1: Each line contains three space-separated integers: h_i, a_i, and c_i. Line i+1 describes block type i.
第1行输入一个整数K. 接下来K行，每行输入三个整数hi，ai，ci．
输出
Line 1: A single integer H, the maximum height of a tower that can be built
一个整数，表示最大高度．
样例
输入
3 7 40 3 5 23 8 2 52 6
输出
48 从底部开始，先放3个方块2，之后3个方块1，接下来6个方块3．不能把3个方块1堆到4个方 块2上，因为这样最高的方块1的顶部高度超过了40.