二维st表秒了，这题纯送

#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
bool Test_MLE_start;
constexpr int N=1005;
int _=1,n,m,k,ans=2e9,a[N][N],maxn[N][N][15],minn[N][N][15];
inline int reads(){
	char c=getchar();
	int x=0,f=1;
	while(!isdigit(c)){if(c=='-') f=-1;c=getchar();}
	while(isdigit(c)){x=(x<<3)+(x<<1)+(c^'0');c=getchar();}
	return x*f;
}
inline void files(){
	freopen("square.in","r",stdin);
	freopen("square.out","w",stdout);
}
inline void clr(){
//	Don't forget!

}
int asksmaxn(int x1,int y1,int x2,int y2){
	int k=log(x2-x1+1)/log(2);
	return max(max(maxn[x1][y1][k],maxn[x2-(1<<k)+1][y1][k]),max(maxn[x1][y2-(1<<k)+1][k],maxn[x2-(1<<k)+1][y2-(1<<k)+1][k]));
}int asksminn(int x1,int y1,int x2,int y2){
	int k=log(x2-x1+1)/log(2);
	return min(min(minn[x1][y1][k],minn[x2-(1<<k)+1][y1][k]),min(minn[x1][y2-(1<<k)+1][k],minn[x2-(1<<k)+1][y2-(1<<k)+1][k]));
}
bool Test_MLE_end;
signed main(){
//	printf("%lf Mb\n",(&Test_MLE_end-&Test_MLE_start-1)/1024.0/1024.0);
//	files();
//	_=reads();
	while(_--){
		clr();n=reads(),m=reads(),k=reads();
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++) minn[i][j][0]=maxn[i][j][0]=a[i][j]=reads();
		}for(int k=1;k<=14;k++){
			for(int i=1;i+(1<<k)-1<=n;i++){
				for(int j=1;j+(1<<k)-1<=m;j++){
					maxn[i][j][k]=max(max(maxn[i][j][k-1],maxn[i][j+(1<<(k-1))][k-1]),max(maxn[i+(1<<(k-1))][j][k-1],maxn[i+(1<<(k-1))][j+(1<<(k-1))][k-1]));
					minn[i][j][k]=min(min(minn[i][j][k-1],minn[i][j+(1<<(k-1))][k-1]),min(minn[i+(1<<(k-1))][j][k-1],minn[i+(1<<(k-1))][j+(1<<(k-1))][k-1]));
				}
			}
		}for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				if(i+k-1>n||j+k-1>m) continue;
				int x1=i,y1=j,x2=i+k-1,y2=j+k-1;
				ans=min(asksmaxn(x1,y1,x2,y2)-asksminn(x1,y1,x2,y2),ans);
			}
		}printf("%d\n",ans);
	}
	return 0;
}
/*
5 4 2
1 2 5 6
0 17 16 0
16 17 2 1
2 10 2 1
1 2 2 2
*/