Nyist 78 Laps Pool

http://acm.nyist.net/JudgeOnline/problem.php?pid=78

Lap Pool time limit:MS | Memory limit:65535 KB Difficulty:4

Describe

There is a pasture, where there are many water supplies, and now the owner of the ranch wants to circle the water supply with a fence to prevent them from drinking water, the pools are labeled with their coordinates, and now you need to write a program that uses the shortest fence to circle the water supply units! (The fence is large enough and variable in length)

Input

The first line of input is N, which represents the test data in N Group (1<=n<=10)
The second line is M, which represents a total of M water supply units (3<=M<=100) for this group of test data.
The next M-line represents the horizontal ordinate of each water supply unit.

Output

Output each fence through the coordinate points of each water supply device, and according to the x-axis coordinate value from small to large output, if the x-axis coordinate value is the same, and then Yasuteru y-coordinate value from small to large output

Sample input

140 01 12) 33 0

Sample output

0 02 33 0

Analysis:

Convex package.

AC Code:

1 //Nyoj 78--Circle Pool Andrew convex packet Algorithm O (NLOGN)2 //outputs the vertices of the convex hull in the order from small to large x after Y3 //4 /*test Data5 96  $7  the8  the9  theTen  the One  the A  $ -  the -  $ the = = 1628 -  - */ -  +#include <cstdio> -#include <cmath> +#include <algorithm> A using namespacestd; at  - Const intMAXP =1010; - Const DoublePzero =0.00001;  -  - structpoint{ -     intx, y; in}p[maxp],chp[maxp*2]; -  to DoubleXJ (Point A, point B, point C) { +     //Vector a->b (b.x-a.x, B.Y-A.Y) -     //Vector a->c (c.x-a.x, C.Y-A.Y) the     return(b.x-a.x) * (C.Y-A.Y)-(c.x-a.x) * (b.y-a.y); * } $ Panax Notoginseng BOOLComp (Point A,point b) { -     return(a.x < b.x) | | ((a.x==b.x) && (a.y<b.y)); the } +  A intAndrewconvexhull (Point *CHP,intN) { the     //calculate convex hull chp[] counter-clockwise save Point +Sort (p, p +N, comp); -     intNCHP =0; $      for(inti =0; I < n; chp[nchp++] = p[i++]) $          while(NCHP >=2&& XJ (chp[nchp-2], chp[nchp-1], P[i]) <=0) -nchp--; -      for(inti = n-1, M = nchp +1; I >=0; chp[nchp++] = p[i--]) the          while(NCHP >= m && XJ (chp[nchp-2], chp[nchp-1], P[i]) <=0) -nchp--;Wuyi     return--NCHP; the } -  Wu voidInitintN) { -     //input About      for(inti =0; I < n; i++) $scanf"%d%d", &p[i].x, &p[i].y); - } -  - voidOutput (intNCHP) { ASort (CHP, CHP +NCHP, comp); +      for(inti =0; i < NCHP; i++){ theprintf"%d%d\n", chp[i].x, chp[i].y); -     } $ } the  the intMain () the { the //freopen ("In.txt", "R", stdin); -     intN;SCANF ("%d",&n); in      while(~SCANF ("%d",&N)) { the  the init (n); About         intNCHP =Andrewconvexhull (CHp, n); the Output (NCHP); the     } the     return 0; +}

Nyist 78 Laps Pool