Check Corners
Time Limit: 2000/10000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2377 Accepted Submission(s): 859
to know the number of them. But soon he find that it is too complex, so he changes his mind, he just want to know whether there is a maximum at the four corners of the sub-matrix, he calls this “Check corners”. It’s a boring job when selecting too many sub-matrices,
so he asks you for help. (For the “Check corners” part: If the sub-matrix has only one row or column just check the two endpoints. If the sub-matrix has only one entry just output “yes”.)
For each test case, the first line contains two integers m, n (1 <= m, n <= 300), which is the size of the row and column of the matrix, respectively. The next m lines with n integers each gives the elements of the matrix which fit in non-negative 32-bit integer.
The next line contains a single integer Q (1 <= Q <= 1,000,000), the number of queries. The next Q lines give one query on each line, with four integers r1, c1, r2, c2 (1 <= r1 <= r2 <= m, 1 <= c1 <= c2 <= n), which are the indices of the upper-left corner
and lower-right corner of the sub-matrix in question.
4 4 10 7
2 13 9 11
5 7 8 20
13 20 8 2
4
1 1 4 4
1 1 3 3
1 3 3 4
1 1 1 1
13 no
20 yes
4 yes
题意:
每次查询求解一个矩阵中的最大值,并判断是否与这个矩阵的四角相等。
/*
二维RMQ的思路与一维的大致相同,都是借助dp先进行预处理,然后快速查询
hhh-2016-01-30 01:59:55
*/
#include <iostream>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <algorithm>
#include <cmath>
#include <queue>
#include <map>
#include <vector>
typedef long long ll;
using namespace std; const int maxn = 305;
int dp[maxn][maxn][9][9];
int tmap[maxn][maxn];
int mm[maxn];
void iniRMQ(int n,int m)
{
for(int i = 1; i <= n; i++)
for(int j = 1; j <= m; j++)
dp[i][j][0][0] = tmap[i][j];
for(int ti = 0; ti <= mm[n]; ti++)
for(int tj = 0; tj <= mm[m]; tj++)
if(ti+tj)
for(int i = 1; i+(1<<ti)-1 <= n; i++)
for(int j = 1; j+(1<<tj)-1 <= m; j++)
{
if(ti)
dp[i][j][ti][tj] =
max(dp[i][j][ti-1][tj],dp[i+(1<<(ti-1))][j][ti-1][tj]);
else
dp[i][j][ti][tj] =
max(dp[i][j][ti][tj-1],dp[i][j+(1<<(tj-1))][ti][tj-1]);
}
} int RMQ(int x1,int y1,int x2,int y2)
{
int k1 = mm[x2-x1+1];
int k2 = mm[y2-y1+1];
x2 = x2 - (1<<k1) +1;
y2 = y2 - (1<<k2) +1;
return
max(max(dp[x1][y1][k1][k2],dp[x1][y2][k1][k2]),
max(dp[x2][y1][k1][k2],dp[x2][y2][k1][k2]));
} int main()
{
int n,m;
mm[0] = -1;
for(int i =1 ; i <= 301; i++)
mm[i] = ((i&(i-1)) == 0)? mm[i-1]+1:mm[i-1];
while(scanf("%d%d",&n,&m)==2)
{
for(int i =1; i <= n; i++)
for(int j = 1; j <= m; j++)
scanf("%d",&tmap[i][j]);
iniRMQ(n,m);
int k;
scanf("%d",&k);
while(k--)
{
int x1,y1,x2,y2;
scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
int ans = RMQ(x1,y1,x2,y2);
printf("%d ",ans); if(ans == tmap[x1][y1] || ans == tmap[x1][y2]
|| ans == tmap[x2][y1]|| ans == tmap[x2][y2])
printf("yes\n");
else
printf("no\n");
}
}
return 0;
}