import std.algorithm, std.conv, std.range, std.stdio, std.string; import std.container; // SList, DList, BinaryHeap import std.math; // math functions alias point = Point!int; alias igrid = Grid!(int, int); alias bgrid = Grid!(bool, int); void main() { auto rd1 = readln.split.to!(int[]), h = rd1[0], w = rd1[1]; auto rd2 = readln.split.to!(int[]), sx = rd2[0]-1, sy = rd2[1]-1, gx = rd2[2]-1, gy = rd2[3]-1; auto ps = point(sy, sx), pg = point(gy, gx); auto ig = igrid(h, w); foreach (i; 0..h) { auto b = readln.chomp; foreach (j; 0..w) ig[i][j] = b[j] - '0'; } auto q = DList!point(ps), bg = bgrid(h, w); bg[ps] = true; while (!q.empty) { auto p = q.front; q.removeFront(); if (p == pg) { writeln("YES"); return; } foreach (np; ig.sibPoints4(p).filter!(np => !bg[np])) if ((ig[p] - ig[np]).abs <= 1) { bg[np] = true; q.insertBack(np); } foreach (np; ig.sibPoints42(p).filter!(np => !bg[np])) if (ig[p] == ig[np]) { bg[np] = true; q.insertBack(np); } } writeln("NO"); } struct Point(T) { T x, y; pure auto opBinary(string op: "+")(Point!T rhs) const { return Point!T(x + rhs.x, y + rhs.y); } pure auto opBinary(string op: "-")(Point!T rhs) const { return Point!T(x - rhs.x, y - rhs.y); } pure auto opBinary(string op: "*")(Point!T rhs) const { return x * rhs.x + y * rhs.y; } pure auto opBinary(string op: "*")(T a) const { return Point!T(x * a, y * a); } pure auto opBinary(string op: "/")(T a) const { return Point!T(x / a, y / a); } pure auto hypot2() const { return x ^^ 2 + y ^^ 2; } } struct Grid(T, U) { import std.algorithm, std.conv, std.range, std.traits, std.typecons; const sibs4 = [Point!U(-1, 0), Point!U(0, -1), Point!U(1, 0), Point!U(0, 1)]; const sibs42 = [Point!U(-2, 0), Point!U(0, -2), Point!U(2, 0), Point!U(0, 2)]; const sibs8 = [Point!U(-1, 0), Point!U(-1, -1), Point!U(0, -1), Point!U(1, -1), Point!U(1, 0), Point!U(1, 1), Point!U(0, 1), Point!U(-1, 1)]; T[][] m; const size_t rows, cols; mixin Proxy!m; this(size_t r, size_t c) { rows = r; cols = c; m = new T[][](rows, cols); } this(T[][] s) { rows = s.length; cols = s[0].length; m = s; } pure auto dup() const { return Grid(m.map!(r => r.dup).array); } ref pure auto opIndex(Point!U p) { return m[p.y][p.x]; } ref pure auto opIndex(size_t y) { return m[y]; } ref pure auto opIndex(size_t y, size_t x) const { return m[y][x]; } static if (isAssignable!T) { auto opIndexAssign(T v, Point!U p) { return m[p.y][p.x] = v; } auto opIndexAssign(T v, size_t y, size_t x) { return m[y][x] = v; } auto opIndexOpAssign(string op, V)(V v, Point!U p) { return mixin("m[p.y][p.x] " ~ op ~ "= v"); } auto opIndexOpAssign(string op, V)(V v, size_t y, size_t x) { return mixin("m[y][x] " ~ op ~ "= v"); } } pure auto validPoint(Point!U p) { return p.x >= 0 && p.x < cols && p.y >= 0 && p.y < rows; } pure auto points() const { return rows.to!U.iota.map!(y => cols.to!U.iota.map!(x => Point!U(x, y))).joiner; } pure auto sibPoints4(Point!U p) { return sibs4.map!(s => p + s).filter!(p => validPoint(p)); } pure auto sibPoints42(Point!U p) { return sibs42.map!(s => p + s).filter!(p => validPoint(p)); } pure auto sibPoints8(Point!U p) { return sibs8.map!(s => p + s).filter!(p => validPoint(p)); } }