1 #include<stdio.h>
2 #include<string.h>
3 #include<algorithm>
4 #include<math.h>
5 using namespace std;
6
7 #define N 310
8 #define inf 0x7fffffff
9
10 struct point
11 {
12 int x,y;
13 }dd[N];
14
15 int n,p;
16 int dp[N][N];
17 int cost[N][N];//边的花费
18
19 bool cmp(const point& a,const point &b){
20 if(a.y == b.y)return a.x < b.x;
21 return a.y < b.y;
22 }
23
24 point save[400],temp[400];
25
26 int xmult(point p1,point p2,point p0){
27 return (p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);
28 }
29
30 int Graham(point *p,int n){
31 int i;
32 sort(p,p + n,cmp);
33 save[0] = p[0];
34 save[1] = p[1];
35 int top = 1;
36 for(i = 0;i < n; i++){
37
38 while(top && xmult(save[top],p[i],save[top-1]) >= 0) top--;
39 save[++top] = p[i];
40 }
41 int mid = top;
42 for(i = n - 2; i >= 0; i--){
43 while(top>mid&&xmult(save[top],p[i],save[top-1]) >= 0) top--;
44 save[++top]=p[i];
45 }
46 return top;
47 }
48
49 int min(int a,int b){return a<b?a:b;};
50
51 void init()
52 {
53 int i,j;
54 for(i = 0;i < n;i++){
55 scanf("%d%d",&dd[i].x,&dd[i].y);
56 }
57 for(i = 0;i < n;i++){
58 dp[i][(i+1)%n] = 0;
59 cost[i][(i+1)%n] = cost[(i+1)%n][i]=0;
60 }
61 }
62
63 int Dp()
64 {
65 int i,j,k;
66 for(i = n-3;i >= 0;i--)//注意三个循环的方向
67 for(j = i+2;j < n;j++)//第一个循环从后往前 第二个循环从前往后是为了保证当前用到的状态都已经被计算过了 已经是最优的了
68 for(k = i+1;k < j;k++)
69 dp[i][j] = min(dp[i][j],dp[i][k]+dp[k][j]+cost[i][k]+cost[k][j]);
70 return dp[0][n-1];
71 }
72
73 int main()
74 {
75 int tot, i, j;
76 while(scanf("%d%d", &n, &p)!=EOF)
77 {
78 init();
79 tot = Graham(dd,n);
80 for(i = 0;i < n;i++)
81 for(j = i+2;j < n;j++){
82 dp[i][j] = inf;
83 cost[i][j] = cost[j][i] = ((abs(save[i].x+save[j].x))*(abs(save[i].y+save[j].y)))%p;
84 }
85 //判断是否是凸多边形
86 if(tot < n){
87 printf("I can't cut.\n");
88 }
89 else{
90 int ans = Dp();
91 printf("%d\n",ans);
92 }
93 }
94 return 0;
95 }
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