WUSTOJ 1337: Car race game（C）树状数组，离散化

题目链接：1337: Car race game

参考资料：⑴ Car race game 树状数组 棋煜，⑵ 树状数组，⑶ 离散化

补充资料：⑴ qsort，⑵ 二分查找

Description

Bob is a game programming specialist. In his new car race game, there are some racers(n means the amount of racers (1<=n<=100000)) racers star from someplace(xi means Starting point coordinate),and they possible have different speed(V means speed).so it possibly takes place to overtake(include staring the same point ). now he want to calculate the maximal amount of overtaking.

有 n 名参赛者，每名参赛者从自己的位置（Xi）以速度（Vi）匀速运动，问最后有多少次超越？

Input

The first line of the input contains an integer n-determining the number of racers. Next n lines follow, each line contains two integer Xi and Vi.(xi means the ith racer’s Starting point coordinate, Vi means the ith racer’s speed.0<Xi, Vi<1000000).

Output

For each data set in the input print on a separate line, on the standard output, the integer that represents the maximal amount of overtaking.

Sample Input

2
2 1
2 2
5
2 6
9 4
3 1
4 9
9 1
7
5 5
6 10
5 6
3 10
9 10
9 5
2 2

Sample Output

1
6
7

分析