ZOJ2859 Matrix Searching 二维RMQ问题

来源：互联网发布：网络筹款平台哪个好编辑：程序博客网时间：2024/04/30 12:44

二维RMQ问题。

#include <cstdio>#include <cmath>#include <cstring>#include <iostream>using namespace std;int f[302][302][9][9];int num[302][302];int n;void init_RMQ(){    int i,j,r,c;    for(i=1;i<=n;i++)      for(j=1;j<=n;j++)        f[i][j][0][0]=num[i][j];    int kr=(int)(log((double)n)/log(2.0));    int kc=kr;    for(i=0;i<=kr;i++)      for(j=0;j<=kc;j++)      {          if(i==0&&j==0) continue;          for(r=1;r+(1<<i)-1<=n;r++)            for(c=1;c+(1<<j)-1<=n;c++)              if(i==0)                f[r][c][i][j]=min(f[r][c][i][j-1],f[r][c+(1<<(j-1))][i][j-1]);              else                f[r][c][i][j]=min(f[r][c][i-1][j],f[r+(1<<(i-1))][c][i-1][j]);      }}int RMQ(int r1,int c1,int r2,int c2){    int kr=(int)(log(double(r2-r1+1))/log(2.0));    int kc=(int)(log(double(c2-c1+1))/log(2.0));    return min(min(f[r1][c1][kr][kc],f[r2-(1<<kr)+1][c1][kr][kc]),min(f[r1][c2-(1<<kc)+1][kr][kc],f[r2-(1<<kr)+1][c2-(1<<kc)+1][kr][kc]));}int main(){    int m;    cin>>m;    while(m--)    {        scanf("%d",&n);        for(int i=1;i<=n;i++)          for(int j=1;j<=n;j++)            scanf("%d",&num[i][j]);        init_RMQ();        int t,r1,c1,r2,c2;        cin>>t;        while(t--)        {            scanf("%d%d%d%d",&r1,&c1,&r2,&c2);            printf("%d\n",RMQ(r1,c1,r2,c2));        }    }    return 0;}

0 0