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 <stdio.h>
#include <algorithm>
using namespace std;
int n, r[100], c[100], dp[100][101];
int main() {
	scanf("%d", &n);
	for(int i = 0; i < n; i++) scanf("%d%d", &r[i], &c[i]), dp[i][i] = 0;
	for(int i = 1; i <= n; i++) {
		for(int j = 0; i + j <= n; j++) {
			dp[j][i + j] = min(dp[j][i + j - 1], dp[j + 1][i + j]) + c[j] * c[i + j - 1];
		}
	}
	printf("%d\n", dp[0][n]);
	return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <map>
#include <set>
#include <queue>
#include <list>
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,a,b) for(int i=int(a);i<int(b);++i)
#define crep(i) for(char i='a';i<='z';i++)
#define psortsecond(A,N) sort(A,A+N,[](const pii &a, const pii &b){return a.second<b.second;});
#define psortfirst(A,N) sort(A,A+N,[](const pii &a, const pii &b){return a.first<b.first;});
#define All(x) (x).begin(),(x).end()
int ctoi(const char c){
  if('0' <= c && c <= '9') return (c-'0');
  return -1;
}
using namespace std;
using pii  = pair<int,int>;
long long gcd(long long a, long long b){return (b == 0 ? a : gcd(b, a%b));}
long long lcm(long long a, long long b){return a*b/gcd(a,b);}
typedef long long ll;
#define MOD 1000000007
#define EPS 10e-8

static const int N = 100;

int main(){
    ll N,P[107],m[107][107];
    cin >> N;
    REP(i,1,N+1){
        cin >> P[i-1] >> P[i];
    }
    REP(i,1,N+1){
        m[i][i]=0;
    }
    REP(l,2,N+1){
        REP(i,1,N-l+2){
            int j=i+l-1;
            m[i][j]=MOD;
            REP(k,i,j+1){
                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;
}

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

#define X 100000001

using namespace std;

int RE[101][101];
int *p;

int rec(int r, int c){
  int M=X;
  int num=c-r;
  int i;
  for(i=0;i<num;i++)M=min(M, RE[r][r+i]+RE[r+i+1][c]+p[r-1]*p[r+i]*p[c]);
  return M;
}

int main(){
  int N;
  cin>>N;
  int i, j;
  for(i=1;i<=N;i++)RE[i][i]=0;
  p=(int *)malloc(sizeof(int)* (N+1));

  cin>>p[0];
  cin>>p[1];
  int bb;
  for(i=2;i<=N;i++){
    cin>>bb;
    cin>>p[i];
  }

  for(i=1;i<N;i++)RE[i][i+1]=p[i-1]*p[i]*p[i+1];

  for(j=0;j<=N-3;j++){
    for(i=3+j;i<=N;i++){
      RE[i-2-j][i]=rec(i-2-j,i);
    }
  }

  cout<<RE[1][N]<<endl;

  return 0;
}

C++: #include <iostream>
using namespace std;
int n, a[111], b[111], dp[111][111];
int main() {
	cin >> n;
	for(int i = 0; i < n; i++) cin >> a[i] >> b[i];
	for(int i = 2; i <= n; i++) {
		for(int j = 0; j <= n - i; j++) {
			int l = j, r = j + i; // [l, r)
			dp[l][r] = 999999999;
			for(int k = l + 1; k < r; k++) {
				dp[l][r] = min(dp[l][r], dp[l][k] + dp[k][r] + a[l] * b[k] * b[r]);
			}
		}
	}
	cout << dp[0][n] << endl;
}

C++: #define _USE_MATH_DEFIMES
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cctype>
#include <climits>
#include <clocale>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

const int MOD = 1'000'000'007;
const int INF = 1'000'000'000; //1e9
const int NIL = -1;
const long long LINF = 1'000'000'000'000'000'000; // 1e18
const long double EPS = 1E-10;

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








int main(){
    int n; std::cin >> n;
    std::vector<int> r(n), c(n);
    for(int i(0); i < n; ++i) std::cin >> r[i] >> c[i];
    //dp[i][j] := iからjまでの計算に必要な回数
    std::vector<std::vector<int>> dp(n, std::vector<int>(n, 0));
    for(int d(1); d < n; ++d){
        for(int i(0), i_len(n - d); i < i_len; ++i){
            int j(i + d);
            dp[i][j] = INF;
            for(int k(i); k < j; ++k){
                chmin(dp[i][j], dp[i][k] + dp[k+1][j] + r[i]*c[k]*c[j]);
            }
        }
    }
    std::cout << dp[0][n-1] << std::endl;
    return 0;
}

C++: // ALDS 1_10_B
#include<cstdio>
#include<cstring>
#include<vector>
#define rep(i,a) for( int i = 0; i != (a); ++i )
#define repi(i,a,b) for( int i = (a); i != (b); ++i )

const int INF = 1<<28;

int n;
std::vector<int> r(100);
std::vector<std::vector<int> > dp( 100, std::vector<int>( 100, INF ) );

int main()
{
	scanf( "%d", &n );
	rep( i, n )
		scanf( "%d%d", &r[i], &r[i+1] );

	rep( i, n )
		dp[i][i] = 0;

	repi( k, 1, n ) rep( i, n-k ) repi( j, i, i+k )
		dp[i][i+k] = std::min( dp[i][i+k], dp[i][j]+dp[j+1][i+k]+r[i]*r[j+1]*r[i+k+1] );	

	printf( "%d\n", dp[0][n-1] );

	return 0;
}

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

using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<pair<int, int>> v;
    for (int i = 0; i < n; ++i) {
        int r, c;
        cin >> r >> c;
        v.emplace_back(r, c);
    }

    vector<vector<int>> dp(n, vector<int>(n, numeric_limits<int>::max()));

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

    auto cost = [&v](int i, int k, int j) {
        return v[i].first * v[k].second * v[j].second;
    };

    // auto p = [&dp, n] {
    //    for (int i = 0; i < n; ++i) {
    //        for (int j = 0; j < n; ++j) {
    //            cout << dp[i][j] << ' ';
    //        }
    //        cout << endl;
    //    }
    //    cout << endl;
    //};
    for (int l = 2; l <= n; ++l) {
        for (int i = 0; i < n - l + 1; ++i) {
            int j = i + l - 1;
            for (int k = i; k < j; ++k) {
                dp[i][j] =
                    min(dp[i][j], dp[i][k] + dp[k + 1][j] + cost(i, k, j));
            }
        }
    }
    cout << dp[0][n - 1] << endl;
}