zoj 2859 RMQ问题，Sparse Table解法

/*The RMQ question, using Sparse Table(ST) algorithm to solve it
*http://www.topcoder.com/tc?module=Static&d1=tutorials&d2=lowestCommonAncestor
*
*initRMQ: M
[logN]
[logN], i,j,u,v
*		j: from 0 to logN (2^j <= N)
*		 v: from 0 to logN (2^v <= N)
*		  i: from 0 to N-1 (i+2^j-1 < N)
*		   u: from o to N-1 (u+2^v-1 < N)
*			M[i][j][u][v] = 1) matrix[i][u], if j==0&&v==0;
*							2) min(M[i][j-1][u][v], M[i+(2^(j-1))][j-1][u][v]), if v==0
*							3) min(M[i][j][u][v-1], M[i][j][u+(2^(v-1))][v-1]), else
*/
#include <stdio.h>

#define min(a,b) (((a)<(b))?(a):(b))
#define N 310

int matrix

;
int M
[9]
[9];

int log_2(int n)
{
int pos = -1,
i = 1;
while(i <= n)
{
if( (i&(i-1)) == 0)
pos += 1;
i++;
}
return pos;
}

void initRMQ(int n)
{
int i, j, u, v;
int logn = log_2(n);

for(j = 0; j <= logn; j++)
for(v = 0; v <= logn; v++)
for(i = 0; i+(1<<j)-1 < n; i++) /*i+(1<<j)-1 < n*/
for(u = 0; u+(1<<v)-1 < n; u++) /*u+(1<<v)-1 < n*/
{
if(j == 0 && v == 0)
{
M[i][j][u][v] = matrix[i][u];
}
else if(v == 0)
{
M[i][j][u][v] = min(M[i][j-1][u][v], M[i+(1<<(j-1))][j-1][u][v]);
}
else
{
M[i][j][u][v] = min(M[i][j][u][v-1], M[i][j][u+(1<<(v-1))][v-1]);
}
}
}

int askRMQ(int i, int j, int u, int v)
{
int k = log_2(u-i+1);
int t = log_2(v-j+1);

int a = min(M[i][k][j][t], M[i][k][v-(1<<t)+1][t]);
int b = min(M[u-(1<<k)+1][k][j][t], M[u-(1<<k)+1][k][v-(1<<t)+1][t]);

return min(a,b);
}

int main()
{
int t;
scanf("%d", &t);
while(t--)
{
int n;
scanf("%d", &n);

int i, j;
for(i = 0; i < n; i++)
for(j = 0; j < n; j++)
scanf("%d", &(matrix[i][j]));

initRMQ(n);

int queries;
scanf("%d", &queries);

while(queries--)
{
int r1, c1, r2, c2;
scanf("%d%d%d%d", &r1, &c1, &r2, &c2);
printf("%d\n", askRMQ(r1-1, c1-1, r2-1, c2-1));
}
}

return 0;
}