【HDOJ】2888 Check Corners

二维RMQ。

/* 2888 */
#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cstdlib>
using namespace std;

#define MAXN 305
#define MAXM 9

int bit[MAXN];
int dp[MAXN][MAXN][MAXM][MAXM];
int n, m;

void RMQ_init() {
    int i, j, k;
    int ii, jj;

    for (i=1; i<=n; ++i)
        for (j=1; j<=m; ++j)
            scanf("%d", &dp[i][j][0][0]);
    for (ii=0; (1<<ii)<=n; ++ii) {
        for (jj=0; (1<<jj)<=m; ++jj) {
            if (ii==0 && jj==0)
                continue;
            for (i=1; i+(1<<ii)-1<=n; ++i) {
                for (j=1; j+(1<<jj)-1<=m; ++j) {
                    if (ii)
                        dp[i][j][ii][jj] = max(dp[i][j][ii-1][jj], dp[i+(1<<(ii-1))][j][ii-1][jj]);
                    else
                        dp[i][j][ii][jj] = max(dp[i][j][ii][jj-1], dp[i][j+(1<<(jj-1))][ii][jj-1]);
                }
            }
        }
    }
}

int RMQ(int lx, int ly, int rx, int ry) {
    int kx = 0, ky = 0;

    while ((1<<(kx+1)) <= (rx-lx+1))
        ++kx;
    while ((1<<(ky+1)) <= (ry-ly+1))
        ++ky;
    return max(
        max(dp[lx][ly][kx][ky], dp[rx-(1<<kx)+1][ly][kx][ky]),
        max(dp[lx][ry-(1<<ky)+1][kx][ky], dp[rx-(1<<kx)+1][ry-(1<<ky)+1][kx][ky])
    );
}

int main() {
    int i, j, k;
    int r1, c1, r2, c2;

    #ifndef ONLINE_JUDGE
        freopen("data.in", "r", stdin);
        freopen("data.out", "w", stdout);
    #endif
    
    while (scanf("%d %d", &n, &m)!=EOF)  {
        RMQ_init();
        scanf("%d", &j);
        while (j--) {
            scanf("%d %d %d %d", &r1, &c1, &r2, &c2);
            if (r1 > r2) swap(r1, r2);
            if (c1 > c2) swap(c1, c2);
            k = RMQ(r1, c1, r2, c2);
            if (k==dp[r1][c1][0][0] || k==dp[r1][c2][0][0] || k==dp[r2][c1][0][0] || k==dp[r2][c2][0][0])
                printf("%d yes
", k);
            else
                printf("%d no
", k);
        }
    }

    return 0;
}