POJ 2019 Cornfields

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 const int maxn = 252;
18 int maxv[maxn][maxn][11],minv[maxn][maxn][11];
19 int n,d,q,s,t;
20 int main() {
21     while(~scanf("%d %d %d",&n,&d,&q)) {
22         for(int i = 0; i < n; i++)
23             for(int j = 0; j < n; j++) {
24                 scanf("%d",&maxv[i][j][0]);
25                 minv[i][j][0] = maxv[i][j][0];
26             }
27         for(int i = 0; i < n; i++){
28             for(int k = 1; (1<<k) < n; k++){
29                 for(int j = 0; j + (1<<k) <= n; j++){
30                     maxv[i][j][k] = max(maxv[i][j][k-1],maxv[i][j+(1<<(k-1))][k-1]);
31                     minv[i][j][k] = min(minv[i][j][k-1],minv[i][j+(1<<(k-1))][k-1]);
32                 }
33             }
34         }
35         int z = log2(d),theMin,theMax;
36         while(q--){
37             scanf("%d %d",&s,&t);
38             --s;
39             --t;
40             theMin = INF;
41             theMax = 0;
42             for(int i = s; i < s + d; i++){
43                 theMin = min(theMin,min(minv[i][t][z],minv[i][t + d - (1<<z)][z]));
44                 theMax = max(theMax,max(maxv[i][t][z],maxv[i][t + d - (1<<z)][z]));
45             }
46             printf("%d\n",theMax - theMin);
47         }
48     }
49     return 0;
50 }