Go: package main

/*
連鎖行列積
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"math"
	"os"
	"strconv"
	"strings"
)

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

type mem *[][]int

func main() {
	scanner := makeScanner(1024)
	n := eGetInt(scanner)
	p := make([]int, n+1)
	for i := 0; i < n; i++ {
		rowcol := eGetInts(scanner)
		p[i] = rowcol[0]
		p[i+1] = rowcol[1]
	}
	m := make([][]int, n)
	for i := 0; i < n; i++ {
		m[i] = make([]int, n)
	}
	// 初期値の格納
	for i := 0; i < n; i++ {
		for j := i; j < n; j++ {
			if i == j {
				m[i][j] = 0 //  同じ行列へのコストは当然0
			} else {
				m[i][j] = math.MaxInt64
			}
		}
	}

	// num : 行列の数. num == 1の場合は初期値0を格納ずみ
	for num := 2; num <= n; num++ {
		// s : スタート行列番号
		for s := 0; s+num <= n; s++ {
			// t : 終了行列番号
			t := s + num - 1
			// k : 仕切
			for k := s; k < t; k++ {
				m[s][t] = min(m[s][t], m[s][k]+m[k+1][t]+p[s]*p[k+1]*p[t+1])
			}
		}
	}
	fmt.Println(m[0][n-1])
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}

// func min(a []int) int {
// 	m := a[0]
// 	for _, v := range a {
// 		if v < m {
// 			m = v
// 		}
// 	}
// 	return m
// }

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

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;
}