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"
	"fmt"
	"os"
	"strconv"
	"strings"
)

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()
// }

C++: 
#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <utility>
    
#define ll (long long)
#define REP(i,n) for(int i = 0;i<(int)n;i++)
#define FOR(i,a,b) for(int i = (a);i < (b);i++)
#define RFOR(i,a,b) for(int i = (a);i>(b);i--)
    
#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <utility>

#define ll (long long)
#define REP(i,n) for(int i = 0;i<(int)n;i++)
#define FOR(i,a,b) for(int i = (a);i < (b);i++)
#define RFOR(i,a,b) for(int i = (a);i>(b);i--)


using namespace std;


int main(void){
    
    int drugnumber;
    int drugcounter;
    /* x????¨????,y?????´????????? */
    double drugeffect[120][120] = {0};
    int i,j,k,l;
    double max = 0;
    double answer[100] = {0};
    
    while(cin >> drugnumber >> drugcounter,drugnumber+drugnumber)
    {
        double combination[120][120] = {0};
        /*??£??\*/
        FOR(j, 1, drugnumber+1)
        FOR(i, 1, drugnumber+1)
        cin >> drugeffect[j][i];
        
        //cout << drugeffect[2][1];
        
        for(k = 1;k <= drugnumber; k++)
            combination[1][k] = 1.0;
        //cout << combination[1][2] << endl;
        
        /* j?????¬?????°,i????????°*/
        
        for(i = 1; i< drugcounter;i++)
            for(j = 1; j<= drugnumber;j++)
            {
                for(k = 1; k<=drugnumber;k++)
                {
                    if((combination[i][j] * drugeffect[j][k]) >= combination[i+1][j])
                        combination[i+1][j] = combination[i][j]*drugeffect[j][k];
                     //cout << combination[i+1][j] << " ";
                    /*
                     if((combination[j][i] * drugeffect[j][i]) >= combination[j][i])
                     combination[j][i+1] = combination[j][i] * drugeffect[j][i];
                     */
                }
            }
        
    
    for(i = 1 ; i<= drugnumber;i++)
        if(max <  combination[drugcounter][i])
            max = combination[drugcounter][i];
    
        answer[l] = max;
        max = 0;
        l++;
        
    }
    
    REP(i,l)
    printf("%.2f\n",answer[i]);
    return 0;
    
}

C++: #include<stdio.h>
double max(double a,double b){return a>b?a:b;}
int main(){
	int n,m;
	int i,j,k;
	double dp[2][100];
	double ch[100][100];
	while(1){
	scanf("%d %d",&n,&m);
	if(n==0)return 0;
	for(i=0;i<n;i++)for(j=0;j<n;j++)scanf("%lf",&ch[i][j]);
	for(i=0;i<n;i++)dp[0][i]=1.0f;
	for(i=1;i<m;i++){
		for(j=0;j<n;j++){
			dp[i%2][j]=0.0f;
			for(k=0;k<n;k++)dp[i%2][j]=max(dp[i%2][j],dp[(i+1)%2][k]*ch[k][j]);
		}
	}
	double ans=0.0f;
	for(i=0;i<n;i++)ans=max(ans,dp[(m+1)%2][i]);
	printf("%.2lf\n",ans);
	}
}

C++: #include <cstdio>
#include <algorithm>
#include <bits/stdc++.h>
using namespace std;
int main()
{
	int n, m;
	while(cin>>n>>m){
		if(!(n&&m))break;
		long double g[n][n];
		/* dp[a][b]??????a?????????b?????\?????????????????????a?????§????????????????????§??? */
		long double dp[m][n];
		for(int i = 0; i < n; i++){for(int j = 0; j < n; j++){scanf("%Lf", &g[i][j]);}}
		for(int i = 0; i < m; i++){
			for(int j = 0; j < n; j++){
				dp[i][j] = 0;
			}
		}
		for(int i = 0; i < n; i++) dp[0][i] = 1;

		for(int i = 1; i < m; i++){
			for(int j = 0; j < n; j++){
				for(int k = 0; k < n; k++){
					dp[i][j] = max(dp[i][j], dp[i - 1][k] * g[k][j]);
				}
			}
		}
		long double res = 0;
		for(int i = 0; i < n; i++){
			res = max(res, dp[m - 1][i]);
		}
		printf("%.2Lf\n", res);
	}

	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<cstdio>

using namespace std;
int n, m;
double cal(double g[][110]) {
  int i, j, k;
  double dp[110][110] = {};
  // double MAX = 0.0;
  double all_MAX = 0.0;
  
  for(i = 1; i <= n; i++) {
    dp[1][i] = 1.0;
  }
  
  for(i = 2; i <= m; i++)
    for(j = 1; j <= n; j++) {
      dp[i][j] = 0.0;
      for(k = 1; k <= n; k++) {
	dp[i][j] = 1.0 * max(dp[i-1][k]*g[k][j], dp[i][j]);
      }
    }
  
  for(i = 1; i <= m; i++) {
    for(j = 1; j <= n; j++){
      //     cout << dp[i][j] << ' ';
      all_MAX = max(dp[i][j], all_MAX);
    }
    //     cout << endl;
  }
  
  return all_MAX;
}

	  
int main() {
  int i, j;
  while(cin >> n >> m, n != 0 || m != 0) {
    double g[110][110] = {};
    
    for(i = 1; i <= n; i++)
      for(j = 1; j <= n; j++)
	cin >> g[i][j];
    printf("%.2lf\n", cal(g));
  }
  
  return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;

int main() {
  int n,m;
  while ( cin >> n >> m, n || m ) {
    double f[101][101];
    double dp[101][101];
    for ( int i = 0; i < n; i++ ) {
      for ( int j = 0; j < n; j++ ) {
	cin >> f[i][j];
      }
    }

    for ( int i = 0; i < m; i++ ) {
      for ( int j = 0; j < n; j++ ) {
	dp[i][j] = 0.0;
      }
    }
    
    for ( int i = 0; i < n; i++ ) dp[0][i] = 1.0;

    for ( int i = 1; i < m; i++ ) {
      for ( int j = 0; j < n; j++ ) {
	for ( int k = 0; k < n; k++ ) {
	  dp[i][j] = max(dp[i][j], dp[i-1][k] * f[k][j]);
	}
      }
    }
    
    double ans = 0;
    for ( int i = 0; i < n; i++ ) ans = max( ans, dp[m-1][i] );
    printf("%.2f\n",ans);
  }	    
  return 0;
}

C++: #include <iostream>
#include <string>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdlib>
using namespace std;

#define rep(i,a) for(int i = 0 ; i < a ; i ++)
#define loop(i,a,b) for(int i = a ; i < b ; i ++)

double dt[102][102];
double dp[102][102];
int n;

double dfs(int d,int v){
	if(abs(dp[d][v]+1)>1e-6)return dp[d][v];
	if(d == 0) return 1.0;
	double r=-1;
	for(int i = 0 ; i < n ; i++){
		r = max(r,dfs(d-1,i) * dt[i][v]);
	}

	return dp[d][v] = r;
}

int main(void){
	int m;
	while(cin>>n>>m,n+m){

		rep(i,n)
			rep(j,n)cin>>dt[i][j],dp[i][j] = -1;
		
		//rep(i,n)rep(j,n)cout<<dt[i][j]<<(j==n-1?'\n':' ');


		double r = 0;
		rep(i,n){
			r = max(r,dfs(m-1,i));
		}
		printf("%lf\n",r);
	}
}

C++: #include <cstdio>
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main(){

	double table[101][101];

	int n,m;
	const int INF=100000000;
	while(cin>>n>>m&&!(n==0&&m==0)){
		for(int i = 0; i < n; i++){
			for(int j = 0; j < n; j++)
				cin>>table[i][j];
		}
		double dp[2][101];
		fill(dp[0],dp[0]+101,1);
		fill(dp[1],dp[1]+101,0);

		double *prv=dp[0];
		double *nxt=dp[1];
		for(int i = 0; i < m; i++){
			for(int j = 0; j < m; j++){
				nxt[i]=max(nxt[i],prv[j]*table[j][i]);
			}
			swap(prv,nxt);
			fill(nxt,nxt+101,0);
		}
		double maxNum=0;
		for(int i = 0; i < m; i++){
			maxNum=max(maxNum,prv[i]);
		}
		double ret = (int)(maxNum*100+0.5)/100;
		printf("%.2f\n",ret);
//		cout<<ret<<endl;
	}

	return 0;
}