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 <algorithm>
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define ll long long
#define ld long double
#define INF 1000000000000000000
typedef pair<ll, ll> pll;
typedef pair<int, int> pint;

struct mat {
    int row = -1;
    int col = -1;
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N;
    cin >> N;
    vector<mat> M(N);
    rep(i, N) {
        int a, b;
        cin >> a >> b;
        M[i].row = a, M[i].col = b;
    }

    vector<vector<ll>> dp(N + 5, vector<ll>(N + 5, INF));
    rep(i, N + 5) { dp[i][i] = 0; }

    for (int w = 1; w < N; w++) {
        for (int i = 0; i < N; i++) {
            if (i + w >= N)
                continue;
            int j = i + w;
            for (int k = i; k < j; k++) {
                ll num_pro = M[i].row * M[k].col * M[j].col;
                dp[i][i + w] =
                    min(dp[i][i + w], dp[i][k] + dp[k + 1][i + w] + num_pro);
            }
        }
    }

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

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

int calcDpTable(int i, int j, int ** dpTable, const int *p) {
	int minValue = INT_MAX; 
	for (int k = i; k < j; ++k) {
		minValue = min(dpTable[i][k - i] + dpTable[k + 1][j - k - 1] + p[i] * p[k + 1] * p[j + 1], minValue);
	}
	//dpTable[0][0] = 1;
	return minValue;
}

int minNumOfMultiplications(const int *p, int n) {
	int **dpTable = new int*[n];
	for (int i = 0; i < n; ++i) {
		dpTable[i] = new int[n - i];
		dpTable[i][0] = 0;
	}

	int d = 1;
	for (int to = n - 2; to >= 0; --to) {
		for (int i = 0; i <= to; ++i) {
			int j = i + d;
			dpTable[i][j - i] = calcDpTable(i, j, dpTable, p);
		}
		++d;
	}
	int ret = dpTable[0][n - 1];
	
	for (int i = 0; i < n; ++i) {
		delete[] dpTable[i];
	}
	delete[] dpTable;

	return ret;
}

int main() {
	int n;
	cin >> n;
	int *p = new int[n + 1];
	for (int i = 0; i < n; ++i) {
		cin >> p[i] >> p[i + 1];
	}
	cout << minNumOfMultiplications(p, n) << endl;
}

C++: #include<cstdio>
#include<climits>
#include<algorithm>
using namespace std;
int AskMCM(int *p,int n){
    int cost[n+1][n+1];
    for(int i = 1;i <= n;++i) cost[i][i] =0;
    for(int l = 2;l <= n; l++){
        for(int i = 1;i <= n - l + 1;i++){
            int j = i+l -1;
            int min_cost = INT_MAX;
            for(int k = i;k < j;++k) min_cost = min(min_cost,cost[i][k] + cost[k+1][j] + p[i-1] * p[k] * p[j]);
            cost[i][j] = min_cost;
        }
    }
    return cost[1][n];
}

int main(){
    int n,r,tmp;
    scanf("%d",&n);
    int p[n+1];
    for(int i = 1;i <= n;++i) scanf("%d %d",&p[i-1],&p[i]);
    printf("%d\n",AskMCM(p,n));
}

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

int main(void){
    int n,i,k,a[110],min,x;
    
    int dp[110][110];
    int length,left,mid,right;
    
    cin>>n;
    
    cin>>a[0]>>a[1];
    for(i=2;i<n+1;i++){
        cin>>x>>a[i];
    }
    
    for(i=0;i<n;i++){
        dp[i][i]=0;
    }

    for(length=1;length<n;length++){
        for(left=0;left<n-length;left++){
            min=1000000000;
            right=left+length;
            for(mid=left;mid<right;mid++){
                x=dp[left][mid]+dp[mid+1][right]+a[left]*a[mid+1]*a[right+1];
                if(x<min)min=x;
            }
            dp[left][right]=min;
        }
    
    }

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

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

int calc(const vector<pair<int, int> >& M, int idx_b, int idx_e) {
    if (idx_b == idx_e) return 0;
    int min = 2e9;
    for (int i = idx_b; i < idx_e; i++) {
        int val = 0;
        val = calc(M, idx_b, i);
        val += calc(M, i + 1, idx_e);
        val += M[idx_b].first * M[i].second * M[idx_e].second;
        if (val < min) min = val;
    }
    return min;
}

int main(){
    int n;
    cin >> n;
    vector<pair<int, int> > M;

    for (int i = 0; i < n; i++) {
        pair<int, int> input;
        cin >> input.first >> input.second;
        M.push_back(input);
    }
    cout << calc(M, 0, M.size() - 1) << endl;

    return 0;
}

C++: #include <iostream>
using namespace std;
#define MAX_SIZE (101)

int main() {
	int n;
	cin >> n;
	// p[i-1], p[i] correspond to M[i]'s row and column size
	int p[MAX_SIZE];
	for (int i=1;i<=n;++i) {
		cin >> p[i-1] >> p[i];
	}
	// [i][j] is a cost for multiplying matrices between M[i] and M[j].
	int dp[MAX_SIZE][MAX_SIZE];
	// [i][i] = 0, i=1,...,n
	for (int i=1;i<=n;++i) {
		dp[i][i] = 0;
	}
	// [i][j], i<j, i=1,...,n
	// j - i = l-1 = 1,2,...,n-1
	// このindexの指定の仕方: なんとなくnまでに合わせたい, l=2,...,nで(l-1)=1,...,n-1になる
	// j = i + (l-1)で, i+1, ..., n まで動く.
	for (int l=2;l<=n;++l) {
		for (int i=1;i<=n-l+1;++i) {
			int j = i + l - 1;// i+1, i+2, ..., n
			dp[i][j] = (1 << 30); 
			for (int k=i;k<j;++k) {
				dp[i][j] = min(dp[i][j], dp[i][k] + dp[k+1][j] + p[i-1] * p[k] * p[j]); 
			}
		}
	}
	cout << dp[1][n] << endl;
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int dp[101][101];
int INF = 1000100100;


int main(){
    int n,r[101],c[101];
    cin >> n;
    for(int i=1; i<n+1; i++){
        cin >>r[i] >> c[i];
    }

    //dp[][]を初期化
    for(int i=0;i<101;i++){
        for(int j=0;j<101;j++){
            dp[i][j]=INF;
        }
    }

    //dp[i][i]=0にする。
    for(int i=1;i<n+1;i++){
        dp[i][i]=0;
    }
    //区間幅をずらしていく。2からスタート
    for(int k=2; k < n+1; k++){
        //対象区間の始点を一つずつ見ていく
        for(int i=1; i+k -1 < n+1; i++){
            //対象区間を2つの小区間にわける
            for(int j =i; j < i+k; j++){
                dp[i][i+k-1]=min(dp[i][i+k-1], dp[i][j]+dp[j+1][i+k-1] + r[i]*c[j]*c[i+k-1]);
            }
        }//添え字が間違ってないか不安。。
    }
    //全区間の答えを出力
    cout << dp[1][n] << endl;
    return 0;
}