Go: // n×nの成長度表に現れる数字を重複を許してm-1個選んで掛け合わせる時の最大値を求める
// ->掛け算型のDP

package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
		"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	for scanner.Scan(){
		buf := strings.Split(scanner.Text(), " ")
		n, _ := strconv.Atoi(buf[0])
		m, _ := strconv.Atoi(buf[1])
		if n == 0 && m == 0 {
			break
		}
		growth_table := make([][]float64, n)
		for i := range growth_table {
			scanner.Scan()
			buf_ := strings.Split(scanner.Text(), " ")
			tmp := make([]float64, n)
			for j := range tmp {
				tmp[j], _ = strconv.ParseFloat(buf_[j], 64)
			}
			growth_table[i] = tmp
		}
		dp := make([][]float64, m)
		for i := range dp {
			dp[i] = make([]float64, n)
		}
		for i := range dp {
			dp[0][i] = 1
		}
		for k := 1; k < m; k++ {
			// k個使うとき...
			for i := 0; i < n; i++ {
				for j := 0; j < n; j++ {
					// 新たにgrowth_table[i][jを使うかどうか
					dp[k][j] = max(dp[k][j], dp[k-1][i]*growth_table[i][j])
					// check(dp)
				}
			}
		}
		ans := 0.0
		for i := 0; i < n; i++ {
			if dp[m-1][i] > ans {
				ans = dp[m-1][i]
			}
		}
		fmt.Printf("%.2f\n", ans)
	}
}

func max(a, b float64) float64 {
	if a < b {
		return b
	}
	return a
}

// func check(dp [][]float64) {
// 	log.Println()
// 	for i := range dp {
// 		log.Println(dp[i])
// 	}
// 	log.Println()
// }

Python: #coding:utf-8
from __future__ import division,print_function
try:
    input = raw_input
    range = xrange
except NameError:
    pass
# 上記のコードはPython2とPython3の違いを一部吸収するためのもの


# N * Mの表をつくる.すべての要素はvにする。
def make_matrix(N,M,v):
    # return [[v for i in range(M)] for j in range(N)]とも書ける。
    ret = []
    for i in range(N):
        l = []
        for j in range(M):
            l.append(v)
        ret.append(l)
    return ret


# gは行列(二次元配列)
def solve(n,m,g):
    # current_max[i][j] = 直前がjの場合のi日目の最大成長度
    current_max = make_matrix(m,n,-1)
    # 最初は何をあげても1.0のまま
    for i in range(n):
        current_max[0][i] = 1.0
    for i in range(1,m):
        # jは次にあげるもの
        for j in range(n):
            # 前に何をあげてたか
            for k in range(n):
                current_max[i][j] = max(current_max[i][j],
                                        current_max[i-1][k]*g[k][j])
    ret = max(current_max[m-1])
    ret = round(ret,3)
    print("%.2f" % ret)

def main():
    while True:
        # 受けとった文字列をintに変換する(リストの内包表記)
        n,m = [int(i) for i in input().split(" ")]
        if n == 0 and m == 0:
            return
        g = []
        for i in range(n):
            g.append([float(x) for x in input().split(" ")])

        solve(n,m,g)
main()

Python: #coding:utf-8
from __future__ import division,print_function
try:
    input = raw_input
    range = xrange
except NameError:
    pass
# 上記のコードはPython2とPython3の違いを一部吸収するためのもの

# http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=916014

# N * Mの表をつくる.すべての要素はvにする。
def make_matrix(N,M,v):
    # return [[v for i in range(M)] for j in range(N)]とも書ける。
    ret = []
    for i in range(N):
        l = []
        for j in range(M):
            l.append(v)
        ret.append(l)
    return ret


# gは行列(二次元配列)
def solve(n,m,g):
    # current_max[i][j] = 直前がjの場合のi日目の最大成長度
    # 負の数にはなりえない。
    current_max = make_matrix(m,n,-1)
    # 最初は何をあげても1.0のまま
    for i in range(n):
        current_max[0][i] = 1.0
    for i in range(1,m):
        # jは次にあげるもの
        for j in range(n):
            # 前に何をあげてたか
            # current_max[i][j] = max(current_max[i-1][k] * g[k][j]) for k in [0,n]
            for k in range(n):
                current_max[i][j] = max(current_max[i][j],
                                        current_max[i-1][k]*g[k][j])
    ret = max(current_max[m-1])
    ret = round(ret,2)
    print("%.2f" % ret)

def main():
    while True:
        # 受けとった文字列をintに変換する(リストの内包表記)
        n,m = [int(i) for i in input().split(" ")]
        if n == 0 and m == 0:
            return
        g = []
        for i in range(n):
            g.append([float(x) for x in input().split(" ")])

        solve(n,m,g)
main()

Python: #coding:utf-8
from __future__ import division,print_function
try:
    input = raw_input
    range = xrange
except NameError:
    pass
# 上記のコードはPython2とPython3の違いを一部吸収するためのもの

# http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=916014

# N * Mの表をつくる.すべての要素はvにする。
def make_matrix(N,M,v):
    # return [[v for i in range(M)] for j in range(N)]とも書ける。
    ret = []
    for i in range(N):
        l = []
        for j in range(M):
            l.append(v)
        ret.append(l)
    return ret


# gは行列(二次元配列)
def solve(n,m,g):
    # current_max[i][j] = 直前がjの場合のi日目の最大成長度
    # 負の数にはなりえない。
    current_max = make_matrix(m,n,-1)
    # 最初は何をあげても1.0のまま
    for i in range(n):
        current_max[0][i] = 1.0
    for i in range(1,m):
        # jは次にあげるもの
        for j in range(n):
            # 前に何をあげてたか
            # current_max[i][j] = max(current_max[i-1][k] * g[k][j]) for k in [0,n]
            for k in range(n):
                current_max[i][j] = max(current_max[i][j],
                                        current_max[i-1][k]*g[k][j])
    ret = max(current_max[m-1])
    ret = round(ret,2)
    print("%.2f" % ret)

def main():
    while True:
        # 受けとった文字列をintに変換する(リストの内包表記)
        n,m = [int(i) for i in input().split(" ")]
        if n == 0 and m == 0:
            return
        g = []
        for i in range(n):
            g.append([float(x) for x in input().split(" ")])

        solve(n,m,g)
main()

Python: while True:
    N, M = map(int, raw_input().split())
    if (N, M) == (0, 0): break
    fert = [map(float, raw_input().split()) for _ in range(N)]
    dp = [[0]*N for _ in range(M)]
    for i in range(N): dp[0][i] = 1.0
    for i in range(M-1):
        for j in range(N):
            dp[i+1][j] = max([dp[i][k]*fert[k][j] for k in range(N)])
    print('{:.2f}'.format(max(dp[M-1])))

Python: # AOJ 0191: Baby Tree
# Python3 2018.6.20 bal4u

while True:
	n, m = list(map(int, input().split()))
	if n == 0: break
	d =  [[0.0 for j in range(n)] for i in range(n)]
	for i in range(n): d[i] = list(map(float, input().split()))
	dp =  [[0.0 for j in range(n)] for i in range(n)]
	for i in range(n): dp[0][i] = 1
	for k in range(1, m):
		for i in range(n):
			for j in range(n):
				dp[k][j] = max(dp[k][j], dp[k-1][i]*d[i][j])
	ans = 0
	for i in range(n):
		if dp[m-1][i] > ans: ans = dp[m-1][i]
	print(format(ans, ".2f"))

Python: while True:
    N, M = map(int, raw_input().split())
    if (N, M) == (0, 0): break
    fert = [map(float, raw_input().split()) for _ in range(N)]
    dp = [[0]*N for _ in range(M)]
    for i in range(N): dp[0][i] = 1.0
    for i in range(M-1):
        for j in range(N):
            dp[i+1][j] = max([dp[i][k]*fert[k][j] for k in range(N)])
    print('{:.2f}'.format(int(max(dp[M-1])*100+0.5)/100))