今日学习在线编程题：点到矩形_码蹄集 矩形

题目来源：码蹄集

https://matiji.net/exam/brushquestion/595/778/B3FCFEC101BD05189BB74D522E019504

参考程序：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
 
typedef struct tagPOINT { //点
	int x, y; //坐标值x和y
} POINT;
typedef struct tagLINE { //线
	POINT s, e; //线的两端
} LINE;
typedef struct tagRECT { //矩形
	POINT lt, rb; //矩形的左上角和右下角
} RECT;
 
float distance_pl(POINT p, LINE l) {
	float d = (l.s.y - l.e.y)*p.x + (l.e.x - l.s.x)*p.y + (l.s.x*l.e.y - l.e.x*l.s.y);
	d = fabs(d) / sqrt((l.e.x - l.s.x)*(l.e.x - l.s.x) + (l.e.y - l.s.y)*(l.e.y - l.s.y));
	return d;
}
 
float distance_pp(POINT p, POINT l) {
	float d = sqrt((p.x - l.x)*(p.x - l.x) + (p.y - p.y)*(p.y - p.y));
	return d;
}
 
int main()
{
	RECT rect;
	POINT p;
	float d, k1, k2;
	int ret;
	ret = scanf("%d %d", &rect.lt.x, &rect.lt.y);
	ret = scanf("%d %d", &rect.rb.x, &rect.rb.y);
	ret = scanf("%d %d", &p.x, &p.y);
	if (rect.lt.x <= p.x&&p.x <= rect.rb.x && rect.rb.y <= p.y&&p.y <= rect.lt.y) {
		printf("0");
	}
	else {
		LINE l1, l2; float dist_min; POINT tmp;
		//矩形x范围内上方或下方
		if (rect.lt.x <= p.x&&p.x <= rect.rb.x) {
			l1.s = rect.lt;
			l1.e = l1.s; l1.e.x = rect.rb.x;
			dist_min = distance_pl(p, l1);
			l2.s = rect.rb;
			l2.e = l2.s; l1.e.x = rect.lt.x;
			dist_min = fmin(dist_min, distance_pl(p, l2));
			printf("%d", (int)(floor(dist_min)));
			return 0;
		}
 
		//矩形y范围内左侧或右侧
		if (rect.lt.x <= p.x&&p.x <= rect.rb.x) {
			l1.s = rect.lt;
			l1.e = l1.s; l1.e.y = rect.rb.y;
			dist_min = distance_pl(p, l1);
			l2.s = rect.rb;
			l2.e = l2.s; l1.e.x = rect.lt.x;
			dist_min = fmin(dist_min, distance_pl(p, l2));
			printf("%d", (int)(floor(dist_min)));
			return 0;
		}
		//其他情况，取最近的顶点距离作为距离
		dist_min = distance_pp(p, rect.lt);
		dist_min = fmin(dist_min, distance_pp(p, rect.rb));
		tmp = rect.lt; tmp.x = rect.rb.x;
		dist_min = fmin(dist_min, distance_pp(p, tmp));
		tmp = rect.lt; tmp.y = rect.rb.y;
		dist_min = fmin(dist_min, distance_pp(p, tmp));
		printf("%d", (int)(floor(dist_min)));
 
	}
 
 
	return 0;
}