输入格式:共2行数据,第一行是以空格为分隔符的数组,共6个元素,分别表示三个点的坐标。第二行是
以空格为分隔符的数组,共2个元素,表示另外点的坐标
输出格式:共1行数据,如果在三角形内部(含边线)输出1,反之输出0
样例(1):
输入:
23 27 94 57 64 58
31 12
输出
0
代码(转)先看看然后我自己再来改改看看
#include <iostream>
#include <stdexcept>
// 判断(x, y), (xx, yy)是否在由(x1, y1)和(x2, y2)组成的直线的同一侧
bool
on_the_same_side(
int
const
x,
int
const
y,
int
const
xx,
int
const
yy,
int
const
x1,
int
const
y1,
int
const
x2,
int
const
y2
) {
int
const
dx21 = x2 - x1, dy21 = y2 - y1,
dx = x - x1, dy = y - y1,
dxx = xx - x1, dyy = yy - y1,
tmp = dxx*dy21 - dyy*dx21;
if
(tmp == 0)
throw
std::invalid_argument(
"不是三角形"
);
return
(dx*dy21 - dy*dx21 >= 0) ==
(tmp > 0);
}
int
main() {
int
x1, y1, x2, y2, x3, y3, x, y;
std::cin >> x1 >> y1
>> x2 >> y2
>> x3 >> y3
>> x >> y;
try
{
std::cout << (
on_the_same_side(x, y, x3, y3, x1, y1, x2, y2) &&
on_the_same_side(x, y, x2, y2, x1, y1, x3, y3) &&
on_the_same_side(x, y, x1, y1, x2, y2, x3, y3)) <<
"\n"
;
}
catch
(std::exception
const
&err) {
std::cerr << err.what() <<
"\n"
;
return
__LINE__;
}
return
0;
}