Go: package main

import (
	"bufio"
	"fmt"
	"io"
	"math"
	"os"
	"strconv"
)

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	fmt.Println(resolve(parseProblem()))
}

type matrixSize struct{ row, col int }

func calcNum(i, j matrixSize) int {
	return i.row * j.col * i.col
}

func parseProblem() (int, []matrixSize) {
	n := scanInt(sc)
	sizes := make([]matrixSize, n)
	for i := 0; i < n; i++ {
		sizes[i] = matrixSize{row: scanInt(sc), col: scanInt(sc)}
	}
	return n, sizes
}

var dp [][]int

func initDP(n int) {
	dp = make([][]int, n+1)
	for i := 0; i < len(dp); i++ {
		dp[i] = make([]int, n+1)
		for j := 0; j < len(dp[i]); j++ {
			dp[i][j] = math.MaxInt64
		}
	}
}

func resolve(n int, sizes []matrixSize) int {
	// TODO 復習
	initDP(n)
	_rec(sizes, 0, n)
	return dp[0][n]
}

func _rec(sizes []matrixSize, l, r int) int {
	if dp[l][r] != math.MaxInt64 {
		return dp[l][r]
	}
	if r-l <= 1 {
		dp[l][r] = 0
		return 0
	}
	num := math.MaxInt64
	for i := l + 1; i < r; i++ {
		v := _rec(sizes, l, i) + _rec(sizes, i, r) + calcNum(matrixSize{sizes[l].row, sizes[i].row}, matrixSize{sizes[i].row, sizes[r-1].col})
		if v < num {
			num = v
		}
	}
	dp[l][r] = num
	return dp[l][r]
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

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

using namespace std;

using i64=long long;

const i64 INF=1LL<<61;

int main() {
    size_t n;
    scanf("%zu", &n);

    vector<int> r(n), c(n);
    for (size_t i=0; i<n; ++i)
        scanf("%d %d", &r[i], &c[i]);

    vector<vector<i64>> dp(n, vector<i64>(n, INF));
    for (size_t i=0; i<n; ++i) dp[i][i] = 0;

    for (size_t k=1; k<n; ++k)
        for (size_t i=0; i+k<n; ++i) {
            size_t j=i+k;
            for (size_t m=i; m<j; ++m) {
                i64 tmp=dp[i][m]+dp[m+1][j]+r[i]*c[j]*c[m];
                if (dp[i][j] > tmp)
                    dp[i][j] = tmp;
            }
        }

    printf("%lld\n", dp[0][n-1]);
    return 0;
}

C++: #include <iostream>
using ll = long long;
using namespace std;

/* initialize */

/* main */
int main() {
    int n, p[101], m[101][101];
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> p[i] >> p[i+1];
    }
    for (int i = 1; i <= n; ++i) m[i][i] = 0;
    for (int l = 2; l <= n; ++l) {
        for (int i = 1; i <= n-l+1; ++i) {
            int j = i+l-1;
            m[i][j] = 1 << 21;
            for (int k = i; k <=j-1; ++k) {
                m[i][j] = min(m[i][j] , m[i][k]+m[k+1][j] +p[i-1]*p[k]*p[j]);
            }
        }
    }
    cout << m[1][n] << "\n";
    return 0;
}

C++: /**
 * 	matrix chain multiplication
 * 	f(n,m) = multiply Mn*M(n+1)*...*M(m-1)*M(m)
 * 	f(n,n) = 1
 * 	r(n)=c(n-1)
 * 	f(n,n+1) = C(n) * R(n) * C(n+1) = c(n) * c(n-1) * c(n+1)
 * 	f(n,k,m) = f(n,k)*f(k+1,m)*C(n)*r(n)*c(k)
 * 	f(n,m) = min(f(n,k,m)
 */

#include <iostream>
#include <cmath>
#include <climits>

using namespace std;

int r[45] = {0};
int a[100][100] = {0};

int f(int n, int m);
int f(int n, int k, int m);


int f(int n, int k, int m)
{
	return f(n,k) * f(k+1,m) + (r[n] * r[k+1] * r[m+1]);
}

int f(int n, int m)
{
	if (n==m) return 1;
	int & ra = a[n][m];
	if (ra) return ra;
	ra = INT_MAX;
	for (int k=n;k<m;k++)
	{
		int ans = f(n,k,m);
		if (ans < ra) ra = ans;
	}
	return ra;
}

int main()
{
	int rr = 0;
	int cc = 0;
	int n = 0;
	cin >> n;
	for (int i=0;i<n;i++)
	{
		cin >> rr >> cc;
		r[i]=rr;
		r[i+1]=cc;
	}
	for (int i=0;i<n-1;i++)
	{
		a[i][i+1] = r[i] * r[i+1] * r[i+2];
	}
	int ans = f(0,n-1);
	cout << ans << endl;
}

C++: #include <iostream>
#include <cstdio>
#include <map>
#define MAX_NUM 100
#define INFTY 1000000000

using namespace std;

//think easy make easy

int n;//num of input


pair<int,int> MatrixChain[MAX_NUM+1];

int calc(int s,int e){//s~eの連鎖行列積の最少計算回数を出力
	int min_time  = INFTY;

	int min_tmp;
	if(s == e){
		return 0;
	}
	for(int i=s;i<e;i++){
		min_tmp = calc(s,i) + calc(i+1,e) 
			+MatrixChain[s].first*MatrixChain[i].second*MatrixChain[e].second;
		if(min_tmp < min_time)
			min_time = min_tmp;
	}
	return min_time;
}

int main(){
	scanf("%d",&n);
	int r,c;//row,column

	for(int i=0;i<n;i++){
		scanf("%d %d",&r,&c);
		MatrixChain[i] = pair<int,int>(r,c);//i:1~n-1
	}

	cout <<calc(0,n-1);

	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <map>
#define MAX_NUM 100
#define INFTY 1000000000
#define NIL -1

using namespace std;

//think easy make easy

int n;//num of input


pair<int,int> MatrixChain[MAX_NUM+1];
map<pair<int,int>,int> mapMC;

int calc(int s,int e){//s~eの連鎖行列積の最少計算回数を出力
	int min_time  = INFTY;
	int min_tmp;

	if(mapMC[pair<int,int>(s,e)] != NIL)
		return mapMC[pair<int,int>(s,e)];

	if(s == e){
		return 0;
	}
	for(int i=s;i<e;i++){
		min_tmp = calc(s,i) + calc(i+1,e) 
			+MatrixChain[s].first*MatrixChain[i].second*MatrixChain[e].second;
		if(min_tmp < min_time)
			min_time = min_tmp;
	}
	mapMC[pair<int,int>(s,e)] = min_time;//メモ
	return min_time;
}

int main(){
	scanf("%d",&n);
	int r,c;//row,column

	for(int i=0;i<n;i++){
		scanf("%d %d",&r,&c);
		MatrixChain[i] = pair<int,int>(r,c);//i:1~n-1
	}
	for(int i=0;i<n;i++){
		for(int j=i;j<n;j++){
			mapMC[pair<int,int>(i,j)] = NIL;
		}
	}

	cout <<calc(0,n-1) <<endl;

	return 0;
}

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

int n;
int r[100],c[100],dp[100][100]={0},ans=0;

int cal(int i,int j,int k)
{
	return r[i]*c[j]*c[k];
}

int main(void)
{
	cin>>n;
	for (int i=1;i<=n;i++)
	{
		cin>>r[i]>>c[i];
	}
	for (int l=2;l<=n;l++)
	{
		for (int i=1;i+l-1<=n;i++)
		{
			//cout<<"i:"<<i<<" l:"<<l<<endl;
			if (l==2) dp[i][i+l-1]=dp[i+l-1][i]=r[i]*c[i]*c[i+l-1];
			else {
				int m=0x7fffff;
				for (int j=i;j<i+l-1;j++)
				{
					int n=dp[i][j]+dp[j+1][i+l-1]+r[i]*c[j]*c[i+l-1];
					m=m<n?m:n;
				}
				dp[i][i+l-1]=m;
			}
			//cout<<"dp[i][i+l-1]="<<dp[i][i+l-1]<<endl;
		}
	}
	/*for (int i=1;i<=n;i++)
	{
		for (int j=1;j<=n;j++)
		{
			cout<<"i:"<<i<<" j:"<<j<<"dp[i][j]:"<<dp[i][j]<<endl;
		}
	}*/
	cout<<dp[1][n]<<endl;
	return 0;
}

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

using namespace std;
static const int N = 1000;

int lcs(string X,string Y){
	int c[N+1][N+1];
	int m=X.size();
	int n=Y.size();
	int maxl=0;
	X=' '+X;
	Y=' '+Y;
	for(int i=1;i<=m;i++) c[i][0]=0;
	for(int j=1;j<=n;j++) c[0][j]=0;
	
	for(int i=1;i<=m;i++){
		for(int j=1;j<=n;j++){
			if(X[i]==Y[j]){
				c[i][j]=c[i-1][j-1]+1;
			}else{
				c[i][j]=max(c[i-1][j],c[i][j-1]);
			}
			maxl=max(maxl,c[i][j]);
		}
	}
	return maxl;
}

int main(){
	string s1,s2;
	int n;cin>>n;
	for(int i=0;i<n;i++){
		cin>>s1>>s2;
		cout<<lcs(s1,s2)<<endl;
	}
	return 0;
}

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

using namespace std;

static const int N = 100;

int main(){
  int n, p[N+1],m[N+1][N+1];

  cin >> n;

  for(int i=1;i<=n;i++){
    cin >> p[i-1] >> p[i];
  }

  for(int i=1;i<=n;i++)m[i][i]=0;

  for(int l=2;l<=n;l++){
    for(int i=1;i<=n;i++){
      int j = i+l-1;
      m[i][j] = (1<<21);
      for(int k=i;k<=j-1;k++){
	m[i][j] = min(m[i][j],m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j]);
      }
    }
  }

  cout << m[1][n] << endl;

  return 0;
}