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
	}

	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
		}
	}
	memo[r] = minCount
	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 "bits/stdc++.h"
#define rep(i,n) for(int i = 0; i < (n); ++i)
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
 
const ll INF = 1e18;

int n;
ll R[105], C[105];
ll dp[105][105];

ll dfs(int l, int r){
    if(l == r) return 0;
    if(dp[l][r] != INF) return dp[l][r];
    ll cost = R[l]*C[r];
    ll res = INF;
    for(int k = l; k < r; k++){
        chmin(res, dfs(l,k) + dfs(k+1,r) + cost*C[k]);
    }
    return dp[l][r] = res;
}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
    cin >> n;
    rep(i,n) cin >> R[i] >> C[i];
    rep(i,n)rep(j,n){
        if(i == j) dp[i][j] = 0;
        else dp[i][j] = INF;
    }
    ll ans = dfs(0, n-1);
    cout << ans << endl;
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll dp[111][111];
ll R[111],C[111];
int main(){
  int n;

  fill(dp[0],dp[110],1000000000000000000LL);

  cin >> n;
  for(int i=0;i<n;i++)
    cin >> R[i] >> C[i];

  for(int i=0;i<n;i++) dp[i][i] = 0;

  for(int k=1;k<n;k++){
    //cout << k << endl;
    for(int i=0;i<n-k;i++){
      for(int j=i;j<i+k;j++){
	///	printf("dp[%d][%d] = %lld + dp[%d][%d] = %lld + %lld * %lld * %lld\n",
	//     i,j,dp[i][j],j+1,i+k,dp[j+1][i+k],R[i],C[i+k],min(C[j],R[j+1]));
	dp[i][i+k] = min( dp[i][i+k],
			  dp[i][j]+dp[j+1][i+k] + 
			  R[i] * C[i+k] * min(C[j],R[j+1]) );
      }
      //  printf("dp[%d][%d] = %lld\n",i,i+k,dp[i][i+k]);
    }
  }

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

C++: #include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i < (n);i++)
#define ALL(obj) (obj).begin(),(obj).end()
using namespace std;

const long long INF = 1LL << 60;
const int MOD = (int)1e9 + 7;
typedef long long ll;
//約数列挙
vector<long long> divisor(long long n) {
    vector<long long> ret;
    for (long long i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            ret.push_back(i);
            if (i * i != n) ret.push_back(n / i);
        }
    }
    //sort(ret.begin(), ret.end()); // 昇順に並べる
    return ret;
}
vector<int> dx={1,0,-1,0};vector<int> dy={0,-1,0,1};

signed main () {
    int m;scanf("%d",&m);
    vector<vector<int>> cost(m+1,vector<int>(m+1));
    vector<int> p(m+1);
    FOR(i,1,m+1){
        int a,b;scanf("%d %d",&a,&b);
        p[i-1] = a;p[i]=b;
    }
    REP(i,m)cost[i][i] = 0;
    int min_cost;
    for (int l = 2; l <= m; l++) {  // 行列の個数
        for (int i = 1; i <= m - l + 1; i++) {
            int j = i + l - 1;
            for (int 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][m] << endl;
}

C++: #include<iostream>
#include<map>
#include<vector>
#include<algorithm>
#include<cmath>
#include<climits>
#include<ctime>
#include<cstring>
#include<numeric>

#define ALL(v) (v).begin(),(v).end()
#define REP(i,p,n) for(int i=p;i<(int)(n);++i)
#define rep(i,n) REP(i,0,n)
#define dump(a) (cerr << #a << "=" << (a) << endl)
#define DUMP(list) cout << "{ "; for(auto nth : list){ cout << nth << " "; } cout << "}" << endl;

using namespace std;

struct matrix {
	int r, c;
	matrix(int r_ = 0, int c_ = 0) : r(r_), c(c_) {}
};

const int INF = 100000000;
vector<vector<int>> dp;

int mul(int r1, int rm, int c2) { return r1 * c2 * rm; }

int main() {
	int N;
	cin >> N;
	int R, C;
	vector<matrix> mats(N);	
	dp.assign(N+1, vector<int>(N+1, INF)); //[l, r)
	rep(i, N) {
		cin >> R >> C;
		mats[i] = matrix(R, C);
	}

	for(int len = 1; len < N+1; ++len) {
		for(int l = 0; l <= N-len; ++l) {
			int r = l + len;	
			if(l+1 == r) {
				dp[l][r] = 0;	
				continue;	
			}		
			for(int m = l+1; m < r; ++m) {	
				int r1 = mats[l].r;
				int rm = mats[m].r;
				int c2 = mats[r-1].c;
				dp[l][r] = min(dp[l][m] + dp[m][r] + mul(r1, rm, c2), dp[l][r]);
			}
		}
	}
	cout << dp[0][N] << endl;
	return 0;
}

C++: #include <iostream>
#include <algorithm>
using namespace std;
static const int N = 101;
int main()
{
    int n;
    int p[N],m[N][N];
    cin>>n;
    for (int i = 1; i <= n; i++)
    {
        cin>>p[i-1]>>p[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<cstdio>
#include<algorithm>
using namespace std;
#define MAX 100
int p[MAX+1] = {0};
int m[MAX+1][MAX+1] = {0};

int main()
{
	int n;
	int a,b;
	scanf("%d" ,&n);
	for(int i=0; i<n; i++)
	{
		scanf("%d%d", &a, &b);
		if(i == 0) p[0] = a;
		p[i+1] = b;
	}

	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 << 30);
			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]);
		}
	}

	printf("%d\n",m[1][n]);

	return 0;


}

C++: #include <bits/stdc++.h>
#define r(i,n) for(int i=0;i<n;i++)
#define int long long
using namespace std;
int dp[111][111],n,L[111],R[111];

int dfs(int l,int r){
	if(dp[l][r]!=-1)return dp[l][r];
	if(l==r)return 0;
	int res=1e17;
	for(int i=l;i<r;i++){
		res=min(res,dfs(l,i)+dfs(i+1,r)+L[l]*R[i]*R[r]);
	}
	return dp[l][r]=res;
}

signed main(){
	memset(dp,-1,sizeof(dp));
	cin>>n;
	r(i,n)cin>>L[i]>>R[i];
	dfs(0,n-1);
	cout<<dp[0][n-1]<<endl;
}