bzoj1047

#include<bits/stdc++.h>
using namespace std;
const int N = 1010;
int a, b, n, ans = 1 << 30;
int d[N][N], mx[N][N], mn[N][N], q1[N], q2[N], mxx[N][N], mnn[N][N];
int main()
{
//  freopen("square.in", "r", stdin);
//  freopen("square.out", "w", stdout);
    scanf("%d%d%d", &a, &b, &n);
    for(int i = 1; i <= a; ++i)
        for(int j = 1; j <= b; ++j) scanf("%d", &d[i][j]);
    for(int i = 1; i <= a; ++i)
    {
        int l1 = 1, r1 = 0, l2 = 1, r2 = 0;
        for(int j = 1; j <= b; ++j)
        {
            while(l1 <= r1 && j - q1[l1] + 1 > n) ++l1;
            while(l1 <= r1 && d[i][j] > d[i][q1[r1]]) --r1;
            while(l2 <= r2 && j - q2[l2] + 1 > n) ++l2;
            while(l2 <= r2 && d[i][j] < d[i][q2[r2]]) --r2;
            q1[++r1] = j;  
            q2[++r2] = j;
            mx[i][j] = d[i][q1[l1]];
            mn[i][j] = d[i][q2[l2]];    
//          printf("mx[%d][%d]=%d mn[%d][%d]=%d\n", i, j, mx[i][j], i, j, mn[i][j]);    
        }
    }
    for(int j = n; j <= b; ++j)
    {
        int l1 = 1, r1 = 0, l2 = 1, r2 = 0;
        for(int i = 1; i <= a; ++i)
        {
            while(l1 <= r1 && i - q1[l1] + 1 > n) ++l1;
            while(l1 <= r1 && mx[i][j] > mx[q1[r1]][j]) --r1;
            while(l2 <= r2 && i - q2[l2] + 1 > n) ++l2;
            while(l2 <= r2 && mn[i][j] < mn[q2[r2]][j]) --r2;
            q1[++r1] = i;
            q2[++r2] = i;
            mxx[i][j] = mx[q1[l1]][j];
            mnn[i][j] = mn[q2[l2]][j];
//          printf("mxx[%d][%d]=%d mnn[%d][%d]=%d\n", i, j, mxx[i][j], i, j, mnn[i][j]);
        }
    }
    for(int i = n; i <= a; ++i)
        for(int j = n; j <= b; ++j) ans = min(ans, mxx[i][j] - mnn[i][j]);
    printf("%d\n", ans);    
//  fclose(stdin);
//  fclose(stdout); 
    return 0;
}