Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list {
		buf.Write([]byte(fmt.Sprintf(" %d", v)))
	}
	buf.Write([]byte("\n"))
	buf.Flush()
}

//solve
//単純な場合
func matrixChainMultiplication() {
	//行列が1つだけのとき
	for i := 1; i <= n; i++ {
		m[i][i] = 0
	}
	for l := 2; l <= n; l++ {
		for i := 1; i <= n-l+1; i++ {
			j := i + l - 1
			m[i][j] = 1 << 21
			//kまでで区切る
			for 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])
			}
		}
	}
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

const MAX = 100

var n int
var p [MAX + 1]int

//m[i][j]: Mi * Mi+1 * ... * Mjを計算するときに必要なスカラー乗算の最小回数
var m [MAX + 1][MAX + 1]int

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 1; i <= n; i++ {

		p[i-1] = nextInt() //行数
		p[i] = nextInt()   //列数
	}

	matrixChainMultiplication()
	fmt.Println(m[1][n])
}

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-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] << endl;
return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)

struct Matrix {
  int low;
  int col;
};

int main() {
  int n; cin >> n;
  vector<Matrix> l(n);
  rep(i, n) {
    int a, b; cin >> a >> b;
    l.at(i).low = a;
    l.at(i).col = b;
  }

  vector<vector<int>> dp(n, vector<int>(n));
  rep(i, n) {
    dp.at(i).at(i) = 0;
  }

  for (int j = 1; j<n; j++) {
    int i = j-1;
    while (i>=0) {
      int k = i;
      int mi = 100000000;
      while (k < j) {
        mi = min(mi, (l.at(i).low * l.at(k).col * l.at(j).col) + dp.at(i).at(k) + dp.at(k+1).at(j));
        k++;
      }
      dp.at(i).at(j) = mi;
      i--;
    }
  }
  cout << dp.at(0).at(n-1) << endl;
}

C++: #include<stdio.h>
#include<cstdlib>

#define INF 2147483647

int n;

void P(){
  printf("\ntest\n");
}

int min(int a, int b){
  return a < b ? a : b;
}

int matrixChainOrder(int *P, int p, int l){
  int i, j, k, m[100][100], q;
  for(i = 1; i < n+1; i++){
    m[i][i] = 0;
  }
  for(i = 1; i < n; i++){ // tonaridousi de keisan
    m[i][i+1] = P[i-1] * P[i] * P[i+1];
  }
  for(i = 2; i <= n-1; i++){ // habahirogeru
    for(j = 1; j+i <= n; j++){ // dokokarahajimerukakimeru
      q = INF;
      for(k = 0; k < i; k++){
	q = min(q, m[j][j+k] + m[j+k+1][j+i] + P[j-1] * P[j+k] * P[j+i]);
	//printf("i:%d j:%d k:%d\n", i, j, k);
      }
      m[j][j+i] = q;
    }
  }

  return m[p][l];
}

int main(){
  int i, *P;

  scanf("%d", &n);
  P = (int *)malloc(sizeof(int) * n + 1);
  for(i = 0; i < n; i++){
    scanf("%d %d", &P[i], &P[i+1]);
  }

  printf("%d\n" ,matrixChainOrder(P, 1, n));

  return 0;
}

C++: #include <vector>
#include <iostream>
#include <string>
#include <climits>

class M{
  int left, right;
  int cnt;
public:
  M(int l = 0, int r = 0, int c = 0):left(l),right(r),cnt(c){}
  const bool is_init(){return left != 0;}
  int get_l(){return left;}
  int get_r(){return right;}
  int get_c(){return cnt;}
  void show(){std::cout << "[ " << left << "," << cnt << "," << right << " ]";}
  M operator+(M &other){
	  M res(left, other.get_r(), cnt + other.get_c() + left * right * other.get_r());
    return res;
  }
  bool operator>(M &other){
	  return cnt > other.get_c();
  }
};
void show_line(int line){
  std::cout << "start dp line " << line << std::endl;
}
void show_all(std::vector<M> &vec){
  for (auto i = vec.begin(); i != vec.end(); ++i){
    i->show();
    std::cout << "-";
  }
  std::cout << std::endl;
}
M Max(0, 0, INT_MAX);
int dp(std::vector<std::vector<M>> memo){
  if (memo.back().size() != 1){
  	std::vector<M> vec;
  	const int n = memo[0].size() - memo.size();
  	for (auto i = 0; i < n; ++i){
      M min = Max;
  		for (auto j = 0; j < memo.size(); ++j){
  			M temp = memo.at(j).at(i) + memo.at(memo.size() - j - 1).at(i + j + 1);
  			if (min > temp){
  				min = temp;
  			}
  		}
  		vec.push_back(min);
  	}
  	memo.push_back(vec);
  	return dp(memo);
	}else{
    return memo.back().back().get_c();
  }
}
int main(){
  int n;
  std::vector<M> v;
  std::cin >> n;
  for (auto i = 0; i < n; ++i){
	  int a, b;
	  std::cin >> a >> b;
	  v.push_back(M(a, b));
  }
  std::vector<std::vector<M>> memo;
  memo.push_back(v);
  std::cout << dp(memo) << std::endl;
  return 0;

}

C++: #include <iostream>
#include <vector>
#include <climits>

int main() {
	int n;
	std::cin >> n;
	std::vector<int> matSize(n + 1);
	std::cin >> matSize[0] >> matSize[1];
	for (int i = 2; i < n + 1; i++) {
		int dammy;
		std::cin >> dammy >> matSize[i];
	}

	std::vector<std::vector<long>> costMat(n, std::vector<long>(n, 0));
	// 動的計画法により解く
	for (int i = 0; i < n - 1; i++) {
		costMat[i][i + 1] = matSize[i] * matSize[i + 1] * matSize[i + 2];
	}
	for (int i = 2; i < n; i++) {
		for (int j = 0; j < n - i; j++) {
			long min = LONG_MAX;
			for (int k = 0; k < i; k++) {
				long cost = costMat[j][j + k] + costMat[j + k + 1][i + j];
				cost += matSize[j] * matSize[j + k + 1] * matSize[i + j + 1];
				if (cost < min) {
					min = cost;
					costMat[j][i + j] = min;
				}
			}
		}
	}
	std::cout << costMat[0][n - 1] << std::endl;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<numeric>
#include<string>
using namespace std;

int main(){
	int n; cin >> n;
	vector<int> p(n+1);
	vector<vector<int> > dp(n, vector<int>(n,-1));
	cin >> p[0] >> p[1];
	int a;
	for (int i=0;i<n;i++){
		cin >> a >> p[i+2];
	}
	//前処理
	for (int i=0;i<n;i++) dp[i][i] = 0;
	for (int i=1;i<n;i++) dp[i-1][i] = p[i-1] * p[i] * p[i+1];
	
	//DPの遷移
	for (int i=0;i<n;i++){
		for (int j=0;j<n-i;j++){
			int a = j, b = j + i;
			if (dp[a][b] != -1) continue;
			//実際の処理
			dp[a][b] = 1e9;
			for (int k=a;k<b;k++){
				int now = dp[a][k] + p[a]*p[k+1]*p[b+1] + dp[k+1][b];
				if (dp[a][b] > now)
				dp[a][b] = now;
			}
		}
	}
	
	cout << dp[0][n-1] << endl;
	return 0;

}

C++: #include <algorithm>
#include <iostream>
#include <string>
using namespace std;
static const int MAX = 100;
#define INF (1 << 30);

int store[MAX][MAX] = {{}};

struct matrix {
  int row;
  int col;
};

int nMul(matrix x, matrix y) { return x.row * x.col * y.col; }

matrix mult(matrix x, matrix y) {
  matrix mat;
  mat.row = x.row;
  mat.col = y.col;
  return mat;
}

int main() {
  matrix mat[MAX];
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> mat[i].row;
    cin >> mat[i].col;
  }

  int mcm[MAX][MAX] = {0};

  for (int j = 1; j < n; j++) {
    for (int i = j-1; i >= 0; i--) {
      int minimum = INF;
      for (int k = i; k < j; k++) {
        int joint = nMul(mult(mat[i], mat[k]), mult(mat[k+1], mat[j]));
        int tmp = mcm[i][k] + mcm[k+1][j] + joint;
        minimum = min(minimum, tmp);
      }
      mcm[i][j] = minimum;
    }
  }

  cout << mcm[0][n-1] << endl;
}