SGU106 The equation[扩展欧几里德算法]

A - The equation

Time Limit:250MS     Memory Limit:4096KB     64bit IO Format:%I64d & %I64u

Submit  Status

Description

There is an equation ax + by + c = 0. Given a,b,c,x1,x2,y1,y2 you must determine, how many integer roots of this equation are satisfy to the following conditions : x1<=x<=x2,   y1<=y<=y2. Integer root of this equation is a pair of integer numbers (x,y).

Input

Input contains integer numbers a,b,c,x1,x2,y1,y2 delimited by spaces and line breaks. All numbers are not greater than 10⁸ by absolute value。

Output

Write answer to the output.

Sample Input

1 1 -3
0 4
0 4

Sample Output

4

题意:

求出 ax+by=-c中的解 x y  符合    x1<=x<=x2  y1<=y<=y2 的解的个数

自己真的挺难理解这个的..然后参考了两个博客

都写的很详细. 直接贴出来去看吧..我感觉自己没这个水平去讲这个

http://blog.csdn.net/volzkzg/article/details/7427233

http://www.cnblogs.com/Rinyo/archive/2012/11/25/2787419.html

主要用到了扩展欧几里德算法  变形一下, 这些博客里面都有说道

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