C++ :

#include <iostream>
using namespace std;
int n,m,p1,p2;
int a[1010][1010];
bool f[1010][1010];//标记某个点是否走过 
int que[1010][3];
int fx[] = {0,1,0,-1};//方向数组
int fy[] = {1,0,-1,0}; 

int main(){
	int i,j,head = 1,tail = 1;
	int x,y; 
	cin>>n>>m>>p1>>p2;
	for(i = 1;i <= n;i++){
		for(j = 1;j <= m;j++){
			cin>>a[i][j];
		}
	}
	
	que[head][1] = p1;
	que[head][2] = p2;
	f[p1][p2] = true;//标记走过了 
	while(head <= tail){
		for(i = 0;i < 4;i++){
			x = que[head][1] + fx[i];
			y = que[head][2] + fy[i];
			//判断边界
			if(x <= n && x >= 1 && y <= m && y >= 1 && a[x][y] <= a[p1][p2] && f[x][y] == false){
				tail++;
				que[tail][1] = x;
				que[tail][2] = y; 
				f[x][y] = true;//标记走过了 
			} 
		}
		
		head++;//统计下一个点的可行路径 
	}
	
	cout<<tail<<endl;
}