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())
}

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#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 <cstdio>
#include <algorithm>
using namespace std;
int m[107], dp[107][107];
int main() {
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
    	scanf("%d%d", &m[i], &m[i + 1]);
	}
	for (int l = 2; l <= n; l++) {
		for (int i = 1; i <= n - l + 1; i++) {
			int j = i + l - 1;
			dp[i][j] = 1e9 + 7;
			for (int k = i; k < j; k++) {
				dp[i][j] = min(dp[i][j], dp[i][k] + dp[k + 1][j] + m[i - 1] * m[k] * m[j]);
			}
		}
	}
	printf("%d\n", dp[1][n]);
    return 0;
}

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

int main(){
	int n, 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;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 <climits>
#include <iostream>
#include <vector>

struct TMatrix
{
	int Row;
	int Col;
	
	TMatrix(int ARow, int ACol);
};

TMatrix::TMatrix(int ARow, int ACol)
: Row(ARow), Col(ACol)
{
}

class TMinimumMultiplications
{
	std::vector<std::vector<int> > FTable;
	const std::vector<TMatrix>& FMatrixChain;
	
	int GetMinimum(int Begin, int End);
public:
	TMinimumMultiplications(const std::vector<TMatrix>& MatrixChain);
	
	int Get(int Begin, int End);
};

TMinimumMultiplications::TMinimumMultiplications(const std::vector<TMatrix>& MatrixChain)
: FMatrixChain(MatrixChain), FTable(MatrixChain.size(), std::vector<int>(MatrixChain.size(), -1))
{
}

int TMinimumMultiplications::GetMinimum(int Begin, int End)
{
	int Minimum = INT_MAX;
	for(int i = Begin; i < End; ++i){
		int Total = Get(Begin, i)
		          + Get(i + 1, End)
		          + FMatrixChain[Begin].Row * FMatrixChain[i + 1].Row * FMatrixChain[End].Col;
		if(Minimum > Total) Minimum = Total;
	}
	return Minimum;
}

int TMinimumMultiplications::Get(int Begin, int End)
{
	if(Begin == End) return 0;
	if(FTable[Begin][End] < 0){
		FTable[Begin][End] = GetMinimum(Begin, End);
	}
	return FTable[Begin][End];
}

int MinimumMultiplicationCount(const std::vector<TMatrix>& MatrixChain)
{
	TMinimumMultiplications Minimum(MatrixChain);
	return Minimum.Get(0, MatrixChain.size() - 1);
}

int main()
{
	int Count;
	std::cin >> Count;
	std::vector<TMatrix> MatrixChain;
	for(int i = 0; i < Count; ++i){
		int Row, Col;
		std::cin >> Row >> Col;
		MatrixChain.push_back(TMatrix(Row, Col));
	}
	
	std::cout << MinimumMultiplicationCount(MatrixChain) << std::endl;
	return 0;
}

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;
}