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())
}

C++: #include<stdio.h>
#include<algorithm>
#define MAX 101
using namespace std;

typedef struct Matrix {
    int r, c;
} Matrix;

Matrix M[MAX];

int Matrix_Chain_Multiplication(int n) {
    int m[MAX][MAX];
    
    if (n==1) return 0;

    for (int i=1; i<=n; i++) {
        m[i][i] = 0;
    }
    
    for (int i=1; i<n; i++) {
        m[i][i+1] = M[i].r*M[i].c*M[i+1].c;
    }

    for (int k=2; k<n; k++) {
        for (int i=1; i+k<=n; i++) {
            m[i][i+k] = (1 << 21);
            for (int j=i; j<i+k; j++) {
                m[i][i+k] = min(m[i][i+k], m[i][j]+m[j+1][i+k]+M[i].r*M[j].c*M[i+k].c);
            }
        }
    }

    return m[1][n];
}

int main() {
    int n;
    
    scanf("%d", &n);
    for (int i=1; i<=n; i++) scanf("%d %d", &M[i].r, &M[i].c);
    
    int minimum = Matrix_Chain_Multiplication(n);

    printf("%d\n", minimum);

    return 0;
}

C++: #include <iostream>
#include <sstream>
#include <cstdio>
#include <stdlib.h>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int n,array[101],m[101][101];
void matrixchainorder(){
  int i,j,l,k;
  for(i=0;i<n+1;i++)
    for(j=0;j<n+1;j++)
      m[i][j]=2000000000;
  for(i=0;i<n+1;i++)m[i][i]=0;
  for(l=2;l<=n;l++){
    for(i=1;i<=n-l+1;i++){
      j=i+l-1;
      for(k=i;k<=j-1;k++){
	m[i][j]=min(m[i][j],m[i][k]+m[k+1][j]+array[i-1]*array[k]*array[j]);
      }
    }
  }
}
int main(){
  cin>>n;
  for(int i=0;i<n;i++)cin>>array[i]>>array[i+1];
  matrixchainorder();
  cout<<m[1][n]<<endl;

  return 0;
}

C++: #include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>

#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define repi(i,a,b) for(int i = (a); i < (b); i++)

using namespace std;

typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;

const int INF=1<<29;
const double EPS=1e-9;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
pii A[200];//firstは行secondを列とする
int dp[200][200];//dp[i][j]:=Ai...Ajの最小スカラー積とする
int n;
int f[200][200];//最適な括弧を挿入する位置
void solve(){
	for(int i =0;i < n;i++){
		for(int j =0;j < n;j++){
			if(i==j)dp[i][j]=0;
			else dp[i][j]=INF;
		}
	}
	
	for(int k =1;k <n;k++){//鎖の数
		for(int i =0;i <n-k;i++){//どこから始めるか
			for(int j =i;j <i+k;j++){//どこに括弧を挟むか
				int tmp =A[i].first*A[j].second*A[i+k].second;
				if(dp[i][i+k] >dp[i][j]+dp[j+1][i+k]+tmp){
					dp[i][i+k]=dp[i][j]+dp[j+1][i+k]+tmp;
					f[i][i+k] =j;
				}
			}
		}
	}
}

void print(int i,int j){//解を表示する
	if(i==j){
		cout <<"A"<<i;
	}else{
		cout <<"(";
		         print(i,f[i][j]);
		         print(f[i][j]+1,j);
		         cout <<")";
}
}


int main(){
	cin>>n;
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	for(int i =0;i < n;i++){
		cin>>A[i].first>>A[i].second;
	}
	solve();
	cout <<dp[0][n-1]<<endl;
	//print(0,n-1);
	return 0;
}

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

int lcs(std::string x, std::string y) {
	int c[101][101];
	int m = x.size();
	int n = y.size();
	int maxl = 0;
	x = ' ' + x;
	y = ' ' + y;
	for (int i = 1; i <= m; i++) {
		c[i][0] = 0;
	}
	for (int i = 1; i <= n; i++) {
		c[0][i] = 0;
	}

	for (int i = 1; i <= m; i++) {
		for (int j = 1; j <= n; j++) {
			if (x[i] == y[j]) {
				c[i][j] = c[i - 1][j - 1] + 1;
			} else {
				c[i][j] = std::max(c[i - 1][j], c[i][j - 1]);
			}
			maxl = std::max(maxl, c[i][j]);
		}
	}
	return maxl;
}


int main() {
	std::string s1, s2;
	int n;
	std::cin >> n;
	for (int i = 0; i < n; i++) {
		std::cin >> s1 >> s2;
		std::cout << lcs(s1, s2) << std::endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
 
#define rep(i,n) for(ll i=0;i<n;++i)
#define ALL(a) (a).begin(),(a).end()
 
using namespace std;
using ll  = long long;
using pll = pair<ll, ll>;
 
const ll MOD  = 1e9+7;
const ll LINF = 1LL << 60;
const int INF = 1e9 + 7;

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

    int len[n+1];
    rep(i, n)cin >> len[i] >> len[i+1];

    ll dp[105][105] = {};//lからrまで行列積の最小の乗算回数

    //連鎖行列積を求める数i
    for(int i = 2; i <= n; ++i){
        for(int l = 1; l+i-1 <= n; ++l){
            int r = i+l-1;
            dp[l][r] = INF;
            //(M_l*...*M_c)*(M_c+1*...*M_r)
            for(ll c = l; c < r; ++c){
                dp[l][r] = min(dp[l][r], dp[l][c] + dp[c+1][r] + len[l-1]*len[c]*len[r]);
            }
        }
    }

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

C++: #include <bits/stdc++.h>
#define N 101
using namespace std;
int A[N];

int mem[N][N],used[N][N];
int dfs(int l,int r){
  if(l == r) return 0;
  if(r - l == 1) return A[l]*A[r]*A[r+1];
  if(used[l][r]++) return mem[l][r];

  int res = 1e9;  
  for(int i=l;i<r;i++){
    int a = dfs(l,i);
    int b = dfs(i+1,r);
    int c = A[l] * A[i+1] * A[r+1];
    res = min(res,a + b + c);
  }
  return mem[l][r] = res;
}

int main(){
  
  int n;
  cin>>n;
  for(int i=0,cnt=0;i<n;i++){
    int a,b;
    cin>>a>>b;
    if(i == 0) A[cnt++] = a;
    A[cnt++] = b;
  }

  cout<<dfs(0,n-1)<<endl;


  return 0;
}

C++: #include <cstdio>
int N, MEMO[100][100], V[100][100];
struct info {
    int r;
    int c;
};
struct info MAT[100];
int DP(int i, int j);
void input(void);
int main(void){
    freopen("in.txt", "r", stdin);
    input();
    printf("%d\n", DP(0, N - 1));
    return 0;
}
int DP(int i, int j){
    if (V[i][j] == 1) return MEMO[i][j];
    V[i][j] = 1;
    if (i >= j) return 0;
    int min = 987654321;
    for(int k = i; k < j; k++){
        int cnd = DP(i, k) + DP(k + 1, j) + MAT[i].r * MAT[k].c * MAT[j].c;
        if (cnd < min) min = cnd;
    }
    MEMO[i][j] = min;
    return min;
}
void input(void){
    scanf("%d", &N);
    for(int i = 0; i < N; i++) scanf("%d%d", &MAT[i].r, &MAT[i].c);
}