use std::io::Write; fn run() { input! { h: usize, w: usize, a: [[u32; w]; h], q: usize, ask: [(usize1, usize1, usize1, usize1); q], } let pos = |x, y| x * w + y; let mut e = vec![]; for i in 0..h { for j in 0..w { if i > 0 { let d = a[i - 1][j].max(a[i][j]); e.push((pos(i - 1, j), pos(i, j), d)); } if j > 0 { let d = a[i][j - 1].max(a[i][j]); e.push((pos(i, j - 1), pos(i, j), d)); } } } e.sort_by_key(|e| e.2); let mut dsu = DSU::new(h * w); let mut dp = vec![250000 + 1; h * w]; for (a, b, w) in e { if let Some((_p, c)) = dsu.unite(a, b) { dp[c] = w; } } let out = std::io::stdout(); let mut out = std::io::BufWriter::new(out.lock()); for (a, b, c, d) in ask { let mut x = pos(a, b); let mut y = pos(c, d); let mut ans = 0; while x != y { if dp[x] > dp[y] { std::mem::swap(&mut x, &mut y); } ans = dp[x]; x = dsu.parent(x).unwrap(); } writeln!(out, "{}", ans).ok(); } } fn main() { run(); } // ---------- begin input macro ---------- // reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 #[macro_export] macro_rules! input { (source = $s:expr, $($r:tt)*) => { let mut iter = $s.split_whitespace(); input_inner!{iter, $($r)*} }; ($($r:tt)*) => { let s = { use std::io::Read; let mut s = String::new(); std::io::stdin().read_to_string(&mut s).unwrap(); s }; let mut iter = s.split_whitespace(); input_inner!{iter, $($r)*} }; } #[macro_export] macro_rules! input_inner { ($iter:expr) => {}; ($iter:expr, ) => {}; ($iter:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($iter, $t); input_inner!{$iter $($r)*} }; } #[macro_export] macro_rules! read_value { ($iter:expr, ( $($t:tt),* )) => { ( $(read_value!($iter, $t)),* ) }; ($iter:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($iter, $t)).collect::>() }; ($iter:expr, chars) => { read_value!($iter, String).chars().collect::>() }; ($iter:expr, bytes) => { read_value!($iter, String).bytes().collect::>() }; ($iter:expr, usize1) => { read_value!($iter, usize) - 1 }; ($iter:expr, $t:ty) => { $iter.next().unwrap().parse::<$t>().expect("Parse error") }; } // ---------- end input macro ---------- //---------- begin union_find ---------- pub struct DSU { p: Vec, } impl DSU { pub fn new(n: usize) -> DSU { assert!(n < std::i32::MAX as usize); DSU { p: vec![-1; n] } } pub fn init(&mut self) { self.p.iter_mut().for_each(|p| *p = -1); } pub fn root(&self, mut x: usize) -> usize { assert!(x < self.p.len()); while self.p[x] >= 0 { x = self.p[x] as usize; } x } pub fn same(&self, x: usize, y: usize) -> bool { assert!(x < self.p.len() && y < self.p.len()); self.root(x) == self.root(y) } pub fn unite(&mut self, x: usize, y: usize) -> Option<(usize, usize)> { assert!(x < self.p.len() && y < self.p.len()); let mut x = self.root(x); let mut y = self.root(y); if x == y { return None; } if self.p[x] > self.p[y] { std::mem::swap(&mut x, &mut y); } self.p[x] += self.p[y]; self.p[y] = x as i32; Some((x, y)) } pub fn parent(&self, x: usize) -> Option { assert!(x < self.p.len()); let p = self.p[x]; if p >= 0 { Some(p as usize) } else { None } } pub fn sum(&self, mut x: usize, mut f: F) -> usize where F: FnMut(usize), { while let Some(p) = self.parent(x) { f(x); x = p; } x } pub fn size(&self, x: usize) -> usize { assert!(x < self.p.len()); let r = self.root(x); (-self.p[r]) as usize } } //---------- end union_find ----------