#yukicoder2855 Move on Grid #入力受取 N, M, K = map(int, input().split()) A = [list(map(int, input().split())) for _ in range(N)] #N, Mでは管理しにくいのでH, Wに。さらにAを一次元化 H, W = N, M B = [A[i][j] for i in range(H) for j in range(W)] #Bの各要素とindexをソート D = {10 ** 9: []} for i, Bi in enumerate(B): try: D[Bi].append(i) except: D[Bi] = [i] key = sorted( D.keys(), reverse = True ) #初期状態の最短路を計算: (0, 0)と(-1, -1)の進入コストも1となる C = [(h + w + 1) for h in range(H) for w in range(W)] #更新。BFSの更新回数が sum(C) <= O(H * W * 2HW) で抑えられる点に注意 dial = [[] for _ in range(H + W)] for Bi in key: #1. D[Bi]の到達コストを1下げる while D[Bi]: assert C[ i := D[Bi].pop() ] >= 1 C[i] -= 1 dial[ C[i] ].append(i) #2. 最短路を更新 Dial algoを回せばOK for c in range( C[-1] + 1 ): while dial[c]: i = dial[c].pop() if C[i] < c: continue assert C[i] == c if i % W < W - 1: if C[ j := i + 1 ] > ( x := C[i] + (B[j] < Bi) ): C[j] = x dial[x].append(j) if i < (H - 1) * W: if C[ j := i + W ] > ( x := C[i] + (B[j] < Bi) ): C[j] = x dial[x].append(j) #3. C[-1] <= Kとなれば答えを出力 if C[-1] <= K: print(Bi) break