> # include <iostream.h>
> # include <stdlib.h>
> struct Point{
> 	int r,c;
> 	int h;
> }Snowarea[100];
> int snowlen[100][4];//记录第i个点向四个方向0左1右2上3下最长滑雪道长度
> 
> int cmp(const void*a,const void*b){
> 	return ((Point*)a)->h-((Point*)b)->h;
> }
> void Findlen(int);
> bool CanGo(int,int,int);
> int max(int);
> void main(){
> 	int row,col;
> 	int i,j,k;
> 	
> 	cin>>row>>col;
> 	k=0;
> 	for (i=1;i<=row;i++){
> 		for (j=1;j<=col;j++){
> 			Snowarea[k].r=i;
> 			Snowarea[k].c=j;
> 			cin>>Snowarea[k].h;
> 			k++;
> 		}
> 	}
> 	qsort(Snowarea,row*col,sizeof(Point),cmp);
> 	Findlen(row*col);	
> }
> void Findlen(int n){
> 	int i,j;
> 	for (i=1;i<n;i++){
> 		for (j=i-1;j>=0;j--){//point j below point i
> 			if (CanGo(i,j,0)==true){//left
> 				snowlen[i][0]=max(j)+1;break;
> 			}
> 			if (CanGo(i,j,1)==true){//right
> 				snowlen[i][1]=max(j)+1;break;
> 			}
> 			if (CanGo(i,j,2)==true){//up
> 				snowlen[i][1]=max(j)+1;break;
> 			}
> 			if (CanGo(i,j,3)==true){//down
> 				snowlen[i][1]=max(j)+1;break;
> 			}
> 		}
> 	}
> 	cout<<max(n-1)+1<<endl;
> }
> bool CanGo(int i,int j,int direction){
> 	switch (direction){
> 	case 0: if (Snowarea[j].r==Snowarea[i].r 
> 				&& Snowarea[j].c==Snowarea[i].c-1
> 				&& Snowarea[i].h>Snowarea[j].h) return true;
> 	case 1: if (Snowarea[j].r==Snowarea[i].r 
> 				&& Snowarea[j].c==Snowarea[i].c+1
> 				&& Snowarea[i].h>Snowarea[j].h) return true;
> 	case 2: if (Snowarea[j].r==Snowarea[i].r-1 
> 				&& Snowarea[j].c==Snowarea[i].c
> 				&& Snowarea[i].h>Snowarea[j].h) return true;
> 	case 3: if (Snowarea[j].r==Snowarea[i].r+1 
> 				&& Snowarea[j].c==Snowarea[i].c
> 				&& Snowarea[i].h>Snowarea[j].h) return true;
> 	}
> 	return false;
> }
> 
> int max(int j){
> 	int temp=0;
> 	int k;
> 	for (k=0;k<4;k++){
> 		if (snowlen[j][k]>snowlen[j][temp])	temp=k;
> 	}
> 	return snowlen[j][temp];
> }