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 <iostream>
#include <algorithm>
#include <vector>
#include<string>
#include <set>
#include <map>
#include <queue>
#include <limits.h>
#include <bitset>
#include <cmath>

using namespace std;

#define rip(i,n,s) for (int i=(s);i<(int)(n);i++)
#define all(a) (a).begin(),(a).end()
typedef long long ll;

struct mat{
    ll r;
    ll c;
};

typedef pair<ll,mat> P;

ll cal(P &x, P &y){
    return x.first+y.first+x.second.r*y.second.r*y.second.c;
}

int main(){
    int n;
    cin >> n;
    vector<mat> da(n);
    rip(i,n,0){
        cin >> da[i].r >> da[i].c;
    }
    vector<vector<P>> dp(n,vector<P>(n));
    rip(i,n,0){
        dp[i][i].first=0;
        dp[i][i].second=da[i];
    }
    rip(i,n,1){
        rip(j,n-i,0){
            dp[j][j+i].first=LLONG_MAX;
            rip(k,i,0){
                dp[j][j+i].first=min(dp[j][j+i].first,cal(dp[j][j+k],dp[j+k+1][j+i]));
            }
            dp[j][j+i].second.r=da[j].r;
            dp[j][j+i].second.c=da[j+i].c;
        }
    }
    cout << dp[0][n-1].first << endl;
}

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

int arr[100];
int dp[100][100];

int findNumOperation(int l, int r)
{
    if(dp[l][r] != -1) return dp[l][r];
    if(r-l==1) return 0;
    else if(r-l==2) return arr[l]*arr[l+1]*arr[r];

    int mn = 99999999;
    for(int i=l+1; i<r; i++){
        int a = findNumOperation(l,i);
        int b = findNumOperation(i,r);
        int c = a+b+(arr[l]*arr[i]*arr[r]);
        if(c<mn) mn=c;
    }
    return mn;
}

int main()
{
    int n;
    cin >> n;
    for(int i=0; i<=n; i++){
        for(int j=0; j<=n; j++){
            dp[i][j] = -1;
        }
    }
    cin >> arr[0] >> arr[1];
    for(int i=2; i<n+1; i++) {
        int a,b;
        cin >> a >> b;
        arr[i] = b;
    }
    int ans = findNumOperation(0, n);
    cout << ans << endl;
}

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

using namespace std;

struct matrix {
  int r;
  int c;
};

int main() {
  vector<matrix> mat;
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    int tmp1,tmp2;
    cin >> tmp1 >> tmp2;
    matrix m = {tmp1, tmp2};
    mat.push_back(m);
  }
  
  int** memo = new int*[n];
  for (int s = 0; s < n; s++) {
    memo[s] = new int[n];
  }

  for (int l = 1; l < n; l++) {
    for (int s = 0; s < n; s++) {
      if (s + l >= n) {
        break;
      }
      
      int minval = 1000000000;
      int sum = 0;
      for (int i = 0; i < l; i++) {
        sum = memo[s][s+i] + memo[s+i+1][s+l];
        matrix m1 = mat[s];
        matrix m2 = mat[s+i];
        matrix m3 = mat[s+l];

        sum += m1.r * m2.c * m3.c;

        minval = min(minval, sum);
      }
      memo[s][s+l] = minval;
    }
  }

  cout << memo[0][n-1] << endl;
  return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
#define INF (99999999)
int main(){

  //-------データの入力------------
  int n;
  cin >> n;
  int row[n];
  int column[n];
  for(int i = 0; i < n; i++){
    cin >> row[i] >> column[i];
  }
  //-----------------------------

  //[始点][終点（始点+幅）]の最小コスト
  int dp[n][n];

  //INFで初期化
  for(int i = 0; i < n; i++){
    for(int j = 0; j < n; j++){
      dp[i][j] = INF;
    }
  }

  //幅0はコスト0
  //dp[i][i+0] = 0
  for(int i = 0; i < n; i++){
    dp[i][i] = 0;
  }

  //幅:j = 0 から探索開始
  for(int j = 0; j < n; j++){
    //始点: i
    for(int i = 0; i < n - j; i++){
      //仕切りを置く位置: k
      // (M_0, M_1, M_2, M_3) | (M_4, M_5)
      for(int k = i + 1; k <= i + j; k++){
        //現在のdp[i][i+j]より小さければ更新
        dp[i][i+j] = min(dp[i][i+j], dp[i][k-1] + dp[k][i+j] + row[i] * column[k-1] * column[i+j]);
      }
    }
  }
  /*
  for(int i = 0; i < n; i++){
    for(int j = 0; j < n; j++){
      cout << dp[i][j] << " ";
    }
    cout << endl;
  }
  */
  //始点０、幅n-1の最小コスト=> n個の行列の連鎖の計算に最低限必要な乗算の回数　を出力
  cout << dp[0][n-1] << endl;
  return 0;
}