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 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[0].r, matrices[len(matrices)-1].c}, v
	}
	if len(matrices) == 0 {
		panic("must not be empty")
	} else if len(matrices) == 1 {
		return matrices[0], 0
	} else if len(matrices) == 2 {
		return calcMultiplication(matrices[0], matrices[1])
	}

	var minCount int = math.MaxInt32

	for i := 0; i < len(matrices)-1; i++ {
		formerMatrices := matrices[:i+1]
		latterMatrices := matrices[i+1:]
		matF, countF := calcMinMatrixChainMultiplication(formerMatrices, Range{0, i}, memo)
		matL, countL := calcMinMatrixChainMultiplication(latterMatrices, Range{i + 1, len(matrices) - 1}, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	return Matrix{matrices[0].r, matrices[len(matrices)-1].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<iostream>
using namespace std;

#define N 100

int main() {
  int i, j, k, l, n, p[N+1], cost[N+1][N+1], min_cost;

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

  // 初期値
  for (i = 1; i <= n; i++) cost[i][i] = 0;

  for (l = 2; l <= n; l++) {  // 行列の個数
    for (i = 1; i <= n - l + 1; i++) {
      j = i + l - 1;
      for (k = i; k < j; k++) {
        if (k == i) min_cost = cost[i][k] + cost[k+1][j] + p[i-1] * p[k] * p[j];
        else min_cost = min(min_cost, cost[i][k] + cost[k+1][j] + p[i-1] * p[k] * p[j]);
      }
      cost[i][j] = min_cost;
    }
  }

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

  return 0;
}

C++: #include<algorithm>
#include<cstdio>
#include<cstring>
#include<limits>
#define rep(i,a) for(int i=0;i<(a);++i)
#define clr(a,v) memset((a),(v),sizeof(a))

const int MAX_N = 100, INF = std::numeric_limits<int>::max()>>2;

int n;
int r[MAX_N], c[MAX_N];
int dp[MAX_N][MAX_N];

int rec( int b, int e )
{
    if( b == e )
        return dp[b][e] = 0;

    if( ~dp[b][e] )
        return dp[b][e];

    int ret = INF;

    rep( i, e-b )
        ret = std::min( ret, rec( b, b+i )+rec( b+i+1, e )+r[b]*c[b+i]*c[e] );

    return dp[b][e] = ret;
}

int main()
{
    scanf( "%d", &n );
    rep( i, n )
        scanf( "%d%d", r+i, c+i );

    clr( dp, -1 );

    printf( "%d\n", rec( 0, n-1 ) );

    return 0;
}

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

int r[105];
int c[105];
int cache[105][105];

int f(int a, int b) {
    if (a == b) return 0;
    if (cache[a][b] == -1) {
        cache[a][b] = 2000000000;
        for (int i = a; i < b; i++) {
            int res = f(a, i) + f(i + 1, b) + r[a] * c[i] * c[b];
            if (res < cache[a][b]) cache[a][b] = res;
        }
    }
    return cache[a][b];
}

int main(void) {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> r[i];
        cin >> c[i];
    }
    memset(cache, -1, sizeof(cache));
    cout << f(0, n-1);
}

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

class MatrixChainMultiplication {
private:
	int n, *r, *c;
	int memory[100][100];
public:
	MatrixChainMultiplication(int _n, int _r[], int _c[]) {
		n = _n;
		r = _r;
		c = _c;
		for (int i=0; i<n; i++) {
			for (int j=1; j<=n; j++) {
				memory[i][j] = INT_MAX;
			}
		}
	}
	int count(int start, int end) {
		if (memory[start][end] != INT_MAX)
			return memory[start][end];
		
		if (start + 1 == end) {
			memory[start][end] = 0;
		} else {
			int temp;
			for (int i=start+1; i<end; i++) {
				temp = count(start, i) + count(i, end) + (r[start] * r[i] * c[end - 1]);
				if (memory[start][end] > temp) memory[start][end] = temp;
			}
		}
		return memory[start][end];
	}
};

int main() {
	int n, r[100], c[100];
	
	cin >> n;
	for (int i=0; i<n; i++) {
		cin >> r[i] >> c[i];
	}
	
	auto mcm = MatrixChainMultiplication(n, r, c);
	
	cout << mcm.count(0, n) << '\n';
	
	return 0;
}

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

#define MAX_SIZE (110)
int P[MAX_SIZE];
int M[MAX_SIZE][MAX_SIZE];

int main()
{
  int N;
  std::cin >> N;
  for (int i = 1; i <= N; ++i)
  {
    std::cin >> P[i - 1] >> P[i];
  }

  for (int i = 0; i <= N; ++i) M[i][i] = 0;
  for (int n = 2; n <= N; ++n)
  {
    for (int i = 1; i <= N - n + 1; ++i)
    {
      int j = i + n - 1;
      M[i][j] = 1 << 30;
      for (int k = i; k < j; ++k)
      {
        M[i][j] = std::min(M[i][j], M[i][k] + M[k + 1][j] + P[i - 1] * P[k] * P[j]);
      }
    }
  }

  std::cout << M[1][N] << std::endl;

  return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int main(){
	int n;
	int p[101], m[101][101];
	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;
}