import std.algorithm, std.conv, std.range, std.stdio, std.string; import std.container; // SList, DList, BinaryHeap import std.math; // math functions void main() { auto rd = readln.split; auto n = rd[0].to!size_t, v = rd[1].to!int; auto o = point(rd[2].to!int - 1, rd[3].to!int - 1); auto lij = n.iota.map!(_ => readln.split.to!(int[])).array; auto gij = new Edge!int[][](n ^^ 2); foreach (j; n.iota) foreach (i; n.iota) { auto p = point(i.to!int, j.to!int); foreach (sib; sibPoints) { auto np = p + sib; if (np.x >= 0 && np.y >= 0 && np.x < n && np.y < n) gij[i + j * n] ~= Edge!int(np.x + np.y * n, lij[np.y][np.x]); } } writeln(calc(gij, o, v) ? "YES" : "NO"); } auto calc(Edge!int[][] gij, point o, int v) { auto n = gij.length; auto d1 = gij.dijkstra2(0, -1); if (v >= d1[n - 1]) return true; if (o.x < 0 || o.y < 0) return false; auto oi = o.x + o.y * n.to!real.sqrt.to!int; if (v < d1[oi]) return false; v = (v - d1[oi]) * 2; auto d2 = gij.dijkstra2(oi, -1); return d2[n - 1] >= v; } struct Point(T) { T x, y; point opBinary(string op)(point rhs) { static if (op == "+") return point(x + rhs.x, y + rhs.y); } } alias Point!int point; const auto sibPoints = [point(-1, 0), point(0, -1), point(1, 0), point(0, 1)]; struct Edge(T) { size_t v; T w; } T[] dijkstra2(T)(Edge!T[][] ai, size_t s, T inf = 0) { auto n = ai.length; auto di = new T[](n); di[] = inf; auto qi = heapify!("a.w > b.w")(Array!(Edge!T)()); void addNext(Edge!T e) { auto v = e.v, w = e.w; di[v] = w; foreach (a; ai[v]) if (di[a.v] == inf) qi.insert(Edge!T(a.v, w + a.w)); } addNext(Edge!T(s, 0)); while (!qi.empty) { auto e = qi.front; qi.removeFront; if (di[e.v] == inf) addNext(e); } return di; }