Go: package main

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

type Matrix struct {
	r int // num of row
	c int // num of column
}

type Range struct {
	start int // index, inclusive
	end   int // index, inclusive
}

func (r Range) length() int {
	return r.end - r.start + 1
}

func calcMultiplication(x, y Matrix) (Matrix, int) {
	if x.c != y.r {
		panic("cannnot calculate")
	}
	return Matrix{x.r, y.c}, x.r * y.c * x.c
}

func calcMinMatrixChainMultiplication(matrices []Matrix, r Range, memo map[Range]int) (Matrix, int) {
	if v, ok := memo[r]; ok {
		return Matrix{matrices[r.start].r, matrices[r.end].c}, v
	}
	if r.length() == 0 {
		panic("must not be empty")
	} else if r.length() == 1 {
		return matrices[r.start], 0
	}

	var minCount int = math.MaxInt32

	for i := 0; i < r.length()-1; i++ {
		formerRange := Range{r.start, r.start + i}
		latterRange := Range{r.start + i + 1, r.end}
		matF, countF := calcMinMatrixChainMultiplication(matrices, formerRange, memo)
		matL, countL := calcMinMatrixChainMultiplication(matrices, latterRange, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	memo[r] = minCount
	return Matrix{matrices[r.start].r, matrices[r.end].c}, minCount
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, _ := nextInt(sc)
	matrices := make([]Matrix, n)
	for i := 0; i < n; i++ {
		r, _ := nextInt(sc)
		c, _ := nextInt(sc)
		matrices[i] = Matrix{r, c}
	}
	memo := make(map[Range]int)
	_, resultCount := calcMinMatrixChainMultiplication(matrices, Range{0, len(matrices) - 1}, memo)
	fmt.Println(resultCount)
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <bits/stdc++.h>
using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)   FOR(i,0,n)
#define ALL(a)     (a).begin(),(a).end()
#define VI         vector<int>
#define MOD 1000000007

using ll = long long int;
using P = pair<int,int>;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

//const ll INF=(ll)1e19;
const int INF=(1<<30);

vector<int> r;
vector<int> c;
int dp[105][105];


int main(){
  int n;
  cin >> n;
  REP(i,n){
    int rr,cc;
    cin >> rr >> cc;
    r.emplace_back(rr);
    c.emplace_back(cc);
  }

  REP(i,n)REP(j,n)dp[i][j]=INF;

  REP(i,n)REP(j,n){
    if(j+i >=n)continue;
    if(i==0){
      dp[j][j] = 0;
    }else{

      FOR(k,j,j+i){
        chmin(dp[j][j+i], dp[j][k] + r[j]*c[k]*c[j+i] + dp[k+1][j+i]);
      }
    }
  }

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

C++: #include <bits/stdc++.h>
#define ALL(a)  (a).begin(),(a).end()
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
typedef pair<long long, long long> Pll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<long long> vll;
typedef vector<vector<long long>> vvll;
template <typename T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template <typename T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const long long INF = 1LL << 60;
const int INT_INF = 1LL << 30;

int N;
vll m(110), n(110);
vvll dp(110, vll(110, INF));

ll res(int l, int r){ //[l, r)での最小回数
  if(dp.at(l).at(r) != INF) return dp.at(l).at(r);
  if(r-l == 1) return dp.at(l).at(r) = 0;
  if(r-l == 2) return dp.at(l).at(r) = m.at(l) * n.at(l) * n.at(r-1);

  ll result = INF;
  for(int i = l+1; i <= r-1; i++){ //[l, i), [i, r)に分割
    chmin(result, res(l, i) + res(i, r) + m.at(l) * m.at(i) * n.at(r-1));
  }
  return dp.at(l).at(r) = result;
}

int main(){
  cin >> N;
  for(int i = 0; i < N; i++){
    cin >> m.at(i) >> n.at(i);
  }

  cout << res(0, N) << endl;
}

C++: // 連鎖行列積 問題
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>

using namespace std;

#define MAX_N 100
#define ELE_NUM 2
// 無効な値の定義
const int INV = -1;

const int colNo = 0;
const int rowNo = 1;
const int IntMAX = 	2147483647;

int ChainedMatrixtMultiplication(int n, int m, int matrixData[][ELE_NUM]);

int main(void)
{

    int n, count;
    int matrix_data[MAX_N + 1][ELE_NUM];

    cin >> n;

    for(int i = 1; i <= n; i++)
    {
        // 行
        cin >> matrix_data[i][colNo];
        // 列
        cin >> matrix_data[i][rowNo];
    }

    count = ChainedMatrixtMultiplication(n, ELE_NUM, matrix_data);
    printf("%d\n", count);

    return 0;
}

// 連鎖行列積の最小の乗算回数を演算する関数
// n : 積を求める行列の数
// m : 行列の情報 : 0 - 行の情報, 1 - 列の情報
// matrixData[][] : 各行列の行、列情報を保持する配列
int ChainedMatrixtMultiplication(int n, int m, int matrixData[][ELE_NUM])
{

    // 第1要素 : 演算開始のNo., 第2要素 : 演算終了のNo.
    int dp[MAX_N + 1][MAX_N + 1];
    int calcResult = 0;

    // 配列の初期化
    for(int i = 0; i <= n; i++)
    {
        for(int j = 0; j <= n; j++)
        {
            dp[i][j] = INV;

            if( i == j )
            {
                // 同じ要素同士の積は演算することが不可能
                dp[i][j] = 0;
            }
        }
    }

    // 行列の演算回数の計算
    // i : 行列の演算をする先頭の要素No.
    // j : 行列の演算をする最後の要素No.
    // k : i 〜 jまでの範囲を移動する変数
    for(int l = 2; l <= n; l++)
    {
        for(int i = 1; i <= n - l + 1; i++)
        {
            int j = i + l - 1;

            dp[i][j] = IntMAX;

            printf("i_s = %d i_e = %d j = %d\n", i, n - l + 1, j);

            for(int k = i; k <= j - 1; k++)
            {
                calcResult = dp[i][k] + dp[k + 1][j]
                            + ( matrixData[i][colNo] * matrixData[k][rowNo] * matrixData[j][rowNo]);

                dp[i][j] = min( dp[i][j], calcResult );
            }
        }
    }

    return dp[1][n];
}

C++: #include<cstdio>
#include<iostream>
#include<vector>
using namespace std;
const int MAX_V = 100;
vector<pair<int,int> > pairs;
int main(){
  int n; scanf("%d",&n);
  for(int i=0;i<n;i++){
    pair<int,int> p;
    scanf("%d %d",&p.first,&p.second);
    pairs.push_back(p);
  }
  long long int sum=0;
  while(pairs.size()>1){
    vector<pair<int,int> >::iterator min_ptr;
    int min=0x7fffffff;
    int mulMin=0x7fffffff;
    for(auto iter=pairs.begin()+1;iter<pairs.end();iter++){
      int localMin = (*(iter-1)).first;
      if(localMin > (*iter).second) localMin = (*iter).second;
      int mul=(*(iter-1)).first*(*iter).second;
      if(min>=localMin){
	if(mulMin>mul){
	  min=localMin;
	  mulMin=mul;
	  min_ptr=iter;
	}
      }
    }
    sum+=(*(min_ptr-1)).first*(*min_ptr).first*(*min_ptr).second;
    (*(min_ptr-1)).second=(*min_ptr).second;
    pairs.erase(min_ptr);
  }
  printf("%lld\n",sum);
}

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

const int N = 100;
const long int Max = pow(10, 10);

int setmatrixmulti(int p[], int n){
    int m[N+1][N+1];
    int minval;
    for(int l=1; l<=n; l++){
        for(int i=1; i<=n - l + 1; i++){
            int j = i + l - 1;
            m[i][j] = Max;
            if(i == j){
                m[i][j] = 0;
            } else {
                for(int k=i; k<j; k++){
                    m[i][j] = min(m[i][j], m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]);
                }
            }
        }
    }
    minval= m[1][n];
    return minval;
}

int main(){
    int n, p1, p2;
    cin >> n;
    int p[n+1];
    for(int i=0; i<n; i++){
        cin >> p1 >> p2;
        if(i == 0){
            p[i] = p1;
            p[i+1] = p2;
        } else {
            p[i+1] = p2;
        }
    }

    // for(int i=0; i<n+1; i++){
    //     cout << p[i] << " " ;
    // }

    int ans = setmatrixmulti(p, n);
    cout << ans << endl;

    return 0;
}