如果跳，那么这条路上所有的点都在图上。搞一个判断就行。写的不好，各种没状态，直接暴力水过。
1 #include <cstdio> 2 #include <cstring> 3 #include <iostream> 4 #include <cmath> 5 #include <algorithm> 6 using namespace std; 7 struct node 8 { 9 int x,y; 10 } p[5001]; 11 bool flag[5001][5001]; 12 bool cmp(node a,node b) 13 { 14 if(a.x == b.x) 15 return a.y < b.y; 16 else 17 return a.x < b.x; 18 } 19 int main() 20 { 21 int r,c,i,j,n,ans,temp,x,y,tx,ty; 22 memset(flag,0,sizeof(flag)); 23 scanf("%d%d",&r,&c); 24 scanf("%d",&n); 25 for(i = 0; i < n; i ++) 26 { 27 scanf("%d%d",&p[i].x,&p[i].y); 28 flag[p[i].x][p[i].y] = 1; 29 } 30 sort(p,p+n,cmp); 31 ans = 2; 32 for(i = 0; i < n; i ++) 33 { 34 for(j = i+1; j < n; j ++) 35 { 36 x = p[j].x - p[i].x; 37 y = p[j].y - p[i].y; 38 tx = p[j].x; 39 ty = p[j].y; 40 if(p[i].x-x <= r&&p[i].x-x >= 1&&p[i].y-y <= c&&p[i].y-y >= 1) 41 continue; 42 for(temp = 2;; temp ++) 43 { 44 tx = tx+x; 45 ty = ty+y; 46 if(tx > r||tx < 1) 47 break; 48 if(ty > c||ty < 1) 49 break; 50 if(!flag[tx][ty]) 51 { 52 temp = 0;//注意这里，SB啊。 53 break; 54 } 55 } 56 ans = max(ans,temp); 57 } 58 } 59 if(ans < 3) 60 printf("0 "); 61 else 62 printf("%d ",ans); 63 return 0; 64 }