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 <algorithm>

using namespace std;

int main()
{
	int n, m;
	double r, a[101][101], dp[101][101];
	
	while(cin>>n>>m && (m+n)){
		for(int i = 0; i < n; i++){
			for(int j = 0; j < n; j++){
				cin >> a[i][j];
			}
		}
		fill(&dp[0][0], &dp[100][100], 0);
		
		for(int i = 0; i < n; i++){
			dp[i][0] = 1.0;
		}
		
		for(int k = 1; k < m; k++){
			for(int i = 0; i < n; i++){
				for(int j = 0; j < n; j++){
					dp[i][k] = max(dp[i][k], dp[i][k-1]*a[j][i]);
				}
			}
		}
		
		r = 0.0;
		for(int i = 0; i < n; i++){
			for(int j = 0; j < m; j++){
				r = max(r, dp[i][j]);
			}
		}
		
		printf("%.2f\n", r);
	}
	
	return 0;
}

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

using namespace std;

vector< vector<double> > hyou(100, vector<double>(100, 0.0));

double seityo(int prev, int type, int limit, double nae) {
	if (limit == 0) {
		return nae;
	} else {
		double MAX = 0.0;
		for (int i = 0; i < type; i++) {
			if (prev != -1) {
				MAX = max(MAX, seityo(i, type, limit-1, nae*hyou[prev][i]));
			} else {
				MAX = max(MAX, seityo(i, type, limit-1, nae));
			}
		}
		return MAX;
	}
}

int main() {
	int n, m;
	while (cin >> n >> m) {
		if (n == 0 && m == 0) {
			break;
		}
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) {
				cin >> hyou[i][j];
			}
		}
		double d = seityo(-1, n, m, 1.0);
		int dd = d * 1000;
		if (dd % 10 >= 5) {
			dd += 10;
		}
		d = dd / 1000.0;
		printf("%.2f\n", d);
	}
	return 0; 
}

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
using namespace std;
double dp[100][100],g[100][100];
int main(){
  int n, m;
  while(cin >> n >> m , n){
    for(int i = 0 ; i < n ; i++ )
      for(int j = 0 ; j < n ; j++ ) cin >> g[i][j];
    fill_n( dp[0], n, 1.0);
    fill_n( dp[1], 9900, 0.0);
    for(int i = 1 ; i < m ; i++ ) //回
      for(int prev = 0 ; prev < n ; prev++ ) // prev
        for(int now = 0 ; now < n ; now++ ) // now
          dp[i][now] = max( dp[i][now], dp[i - 1][prev] * g[prev][now]);

    cout << fixed << setprecision(2) << *max_element( dp[m - 1], dp[m - 1] + n ) << endl;
  }
}

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];
		rep(i,102)rep(j,102)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("%.2f\n",r+1/2*(1/10)*2);
	}
}

C++: #include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int n,m;
double dp[101][100];
double g[100][100];
main()
{
	while(cin>>n>>m,n)
	{
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<n;j++)cin>>g[i][j];
			for(int j=0;j<=m;j++)dp[j][i]=1;
		}
		for(int i=0;i<m-1;i++)
		{
			for(int j=0;j<n;j++)
			{
				for(int k=0;k<n;k++)
				{
					dp[i+1][j]=max(dp[i+1][j],dp[i][k]*g[k][j]);
				}
			}
		}
		double ans=1;
		for(int i=0;i<n;i++)ans=max(ans,dp[m-1][i]);
		ans=round(ans*100);
		cout<<ans/100<<endl;
	}
}

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][k])
                        combination[i+1][k] = 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 <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define RFOR(i,a,b) for(int i=(b) - 1;i>=(a);i--)
#define REP(i,n) for(int i=0;i<(n);i++)
#define RREP(i,n) for(int i=n-1;i>=0;i--)

#define PB push_back
#define INF INT_MAX/3
#define ALL(a) (a).begin(),(a).end()
#define CLR(a) memset(a,0,sizeof(a))

typedef long long int ll;

using namespace std;

int main(){
    while(true){
	int m,n;
	cin >> n >> m;
	vector< vector<double> > d(n,vector<double>(n,0.0) );
	if(n == 0 && m == 0) break;
	REP(i,n)REP(j,n) cin >> d[i][j];
	double ans = 0.0;
	vector<double> a(n);
	double dp[2][101];
	memset(dp,1,sizeof(dp));
	REP(i,101) dp[0][i] = 1;
	REP(i,m-1){
	    REP(j,101) dp[1][i] = 0;
	    REP(j,n){
		REP(k,n){
		    dp[1][j] = max(dp[1][j],dp[0][j] * d[k][j]);
		}
	    }
	    swap(dp[0],dp[1]);
	}
	REP(i,n) ans = max(dp[0][i],ans);
	int t = ans * 1000;
	t = t % 10;
	if(t >= 5) ans += 0.01;
	printf("%.2f\n",ans);
    }
    return 0;
}