Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func min(x, y int) int {
	if x < y {
		return x
	}
	return y
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

func main() {
	scanner.Split(bufio.ScanWords)

	n := nextInt()
	m := make([][]int, n)
	sizes := make([][]int, n)
	for i := 0; i < n; i++ {
		sizes[i] = []int{nextInt(), nextInt()}
		m[i] = make([]int, n)
	}
	// fmt.Println(sizes)

	for w := 1; w < n; w++ {
		for i := 0; i < n-w; i++ {
			j := i + w
			minBetweenIandJ := 10000000
			for k := i; k < j; k++ {
				// fmt.Println(i, j, k, m[i][k], m[k+1][j], sizes[i][0]*sizes[k][1]*sizes[j][1])
				minBetweenIandJ = min(minBetweenIandJ, m[i][k]+m[k+1][j]+sizes[i][0]*sizes[k][1]*sizes[j][1])
			}
			m[i][j] = minBetweenIandJ
		}
	}
	// for i := 0; i < len(m); i++ {
	// 	fmt.Println(stringifyArray(m[i]))
	// }
	fmt.Println(m[0][n-1])
}

C++: #include<string>
#include <utility>
#include <iostream>
 
#define MAX 100

#define INF 100000000

int left[MAX];
int right[MAX];

int DP[MAX][MAX];

int main(){
  int n;
  std::cin >> n;

  for(int i = 0; i < n; i++){
    std::cin >> left[i];
    std::cin >> right[i];
  }
  
  for(int i = 0; i < MAX; i++){
    for(int j = 0; j < MAX; j++){
      DP[i][j] = INF;
   }
  }

  for(int k = 0; k < n; k++){
    for(int l = 0; l + k < n; l++){
      int r = l + k;
      
      if(k == 0){
	DP[l][r] = 0;
      }else if(k == 1){
	DP[l][r] = left[l] * right[l] * right[r];
      }else{
	for(int t = l; t < r; t++){
	 
	  DP[l][r] = std::min(DP[l][r], DP[l][t] + DP[t + 1][r] + left[l] * right[t] * right[r]);
	}

	// printf("%d %d %d\n", l, r, DP[l][r]);
      }
    }
  }
  
  std::cout << DP[0][n-1] << std::endl;
}

C++: #include <bits/stdc++.h>

using namespace std;

using ll = long long;
using P = pair<ll, ll>;
using Graph = vector<vector<ll>>;
#define rep(i, n) for(ll i=0;i<(ll)(n);i++)
#define rep2(i, m, n) for(ll i=m;i<(ll)(n);i++)
#define rrep(i, n, m) for(ll i=n;i>=(ll)(m);i--)
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
const int ddx[8] = {0, 1, 1, 1, 0, -1, -1, -1};
const int ddy[8] = {1, 1, 0, -1, -1, -1, 0, 1};
const ll MOD = 1000000007;
const ll INF = 1000000000000000000L;
#ifdef __DEBUG

/**
 * For DEBUG
 * https://github.com/ta7uw/cpp-pyprint
 */
#include "cpp-pyprint/pyprint.h"

#endif

ll N;
vector<P> A;
vector<vector<ll>> dp;

ll dfs(ll l, ll r) {
    if (dp[l][r] != INF) {
        return dp[l][r];
    }
    if (abs(l - r) == 1) {
        return dp[l][r] = 0;
    } else if (abs(l - r) == 2) {
        P f = A[l];
        P s = A[l + 1];
        return dp[l][r] = f.first * f.second * s.second;
    }

    ll res = INF;
    for (ll k = l + 1; k < r; k++) {
        res = min(res, dfs(l, k) + dfs(k, r) + A[l].first * A[r - 1].second * A[k - 1].second);
    }
    return dp[l][r] = res;
}

void solve() {
    cin >> N;
    A.resize(N);
    dp.resize(N + 1, vector<ll>(N + 1, INF));
    rep(i, N) cin >> A[i].first >> A[i].second;
    cout << dfs(0, N) << '\n';
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    solve();
    return 0;
}

C++: //
//  main.cpp
//  ALDS1_10_B:MatrixChainMultiplication
//
//  Created by Kang on 2020/8/14.
//  Copyright © 2020 Kang. All rights reserved.
//

#include <cstdio>
using namespace std;

int main(int argc, const char * argv[]) {
    int n;
    int p[101];       // 矩阵维数
    int dp[101][101]; // 只用上三角
    
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
        scanf("%d%d", &p[i], &p[i+1]);
    }
    // j-i = dif, dif = 0, 1, ..., n - 1
    for (int dif = 0; dif < n; dif++) {     // dif = j - i;
        for (int i = 1; i <= n-dif; i++) {  // i表示行数
            if(dif == 0) {dp[i][i] = 0;}
            else {
                int min = ~(1 << 31);
                int tmp;
                for (int k = i; k < i + dif; k++) {
                    tmp = dp[i][k] + dp[k + 1][i+dif] + p[i-1] * p[k] * p[i + dif];
                   /*printf("dp[%d][%d] + dp[%d][%d] + p[%d] * p[%d] * p[%d] = %d\n",
                          i, k, k+1, i+dif, i-1, k, i+dif, tmp);*/
                    if (tmp < min) min = tmp;
                }
                dp[i][i+dif] = min;
                
                // printf("dp[%d][%d] = %d\n",i, i+dif, min);
                // printf("--------------------\n");
            }
        }
    }
    printf("%d\n", dp[1][n]);
    
    return 0;
}

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 <iostream>
#include <iomanip>
#include <utility>
#include <cmath>
#include <random>
#include <vector>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <algorithm>
using namespace std;

#define rep(i,n) for(int i = 0; i<n; ++i)
#define REP(i,n) for(int i = 1; i<=n; ++i)
#define all(x) begin(x),end(x)
#define show(obj) {for(auto x:obj)cout<<x<<' ';cout<<endl;}
typedef long long ll;
typedef pair<int,int> ip;
typedef pair<ll,ll> lp;
const int inf = 1001001000;
const ll INF = 1LL<<60;
const int MOD = (int)1e9 + 7;

template<class T> inline bool chmin(T& a, T b) {if (a > b) { a = b; return true; } return false;}

int main(){
	int N; cin>>N;
	vector<ip> M(N);
	rep(i,N)cin>>M[i].first>>M[i].second;
	vector<vector<int>> dp(N,vector<int>(N,inf));
	rep(i,N)dp[i][i] = 0;
	for(int i = 1; i<N; ++i){
		int l = 0, r = i;
		for(int j = 0; j<N-i; ++j){
			for(int k = l; k<r; ++k){
				chmin(dp[l][r], dp[l][k] + dp[k+1][r] + M[l].first * M[k].second * M[r].second);
				// chmin(dp[l][r], dp[l][r-1] + M[l].first * M[r].first * M[r].second);
			}
			// printf("[l,r] => [%d,%d]\n",l,r);
			++l; ++r;
		}
	}
	cout<<dp[0][N-1]<<endl;
	return 0;
}

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

int nlist[110];
int dp[110][110];

int main(){
  int n;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>nlist[i]>>nlist[i+1];
  }
  for(int i=1;i<n;i++){
    for(int j=0;j<n-i;j++){
      dp[j][j+i]=1<<30;
      for(int k=0;k<i;k++){
	dp[j][j+i]=min(dp[j][j+i],dp[j][j+k]+dp[j+k+1][j+i]+nlist[j]*nlist[j+k+1]*nlist[j+i+1]);
      }
    }
  }
  cout<<dp[0][n-1]<<endl;
  return 0;
}