[POJ2007]Scrambled Polygon（计算几何 极角排序）

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <iomanip>
 4 #include <cstring>
 5 #include <climits>
 6 #include <complex>
 7 #include <fstream>
 8 #include <cassert>
 9 #include <cstdio>
10 #include <bitset>
11 #include <vector>
12 #include <deque>
13 #include <queue>
14 #include <stack>
15 #include <ctime>
16 #include <set>
17 #include <map>
18 #include <cmath>
19 
20 using namespace std;
21 
22 typedef struct Point {
23     int x;
24     int y;
25     Point() {}
26     Point(int xx, int yy) : x(xx), y(yy) {}
27     Point operator +(const Point& b) const { return Point(x+b.x, y+b.y); }
28     Point operator -(const Point& b) const { return Point(x-b.x, y-b.y); }
29     int operator ^(const Point& b) const { return x * b.y - y * b.x; }
30     int operator *(const Point& b) const { return x * b.x + y * b.y; }
31 }Point;
32 
33 typedef struct Line {
34     Point u;
35     Point v;
36     Line() {}
37     Line(Point uu, Point vv) : u(uu), v(vv) {}
38 }Line;
39 
40 int xmulti(Point p0, Point p1, Point p2) {
41     return (p1 - p0) ^ (p2 - p0);
42 }
43 
44 const int maxn = 111;
45 Point pp[maxn];
46 int n;
47 
48 int cmp(Point a, Point b) {
49     Point t(0, 0);
50     return xmulti(t, b, a) < 0;
51 }
52 
53 int main() {
54     // freopen("in", "r", stdin);
55     for(n = 0; ~scanf("%d %d", &pp[n].x, &pp[n].y); n++);
56     sort(pp+1, pp+n, cmp);
57     for(int i = 0; i < n; i++) {
58         printf("(%d,%d)\n", pp[i].x, pp[i].y);
59     }
60     return 0;
61 }