Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list {
		buf.Write([]byte(fmt.Sprintf(" %d", v)))
	}
	buf.Write([]byte("\n"))
	buf.Flush()
}

//solve
//単純な場合
func matrixChainMultiplication() {
	//行列が1つだけのとき
	for i := 1; i <= n; i++ {
		m[i][i] = 0
	}
	for l := 2; l <= n; l++ {
		for i := 1; i <= n-l+1; i++ {
			j := i + l - 1
			m[i][j] = 1 << 21
			//kまでで区切る
			for 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])
			}
		}
	}
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

const MAX = 100

var n int
var p [MAX + 1]int

//m[i][j]: Mi * Mi+1 * ... * Mjを計算するときに必要なスカラー乗算の最小回数
var m [MAX + 1][MAX + 1]int

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 1; i <= n; i++ {

		p[i-1] = nextInt() //行数
		p[i] = nextInt()   //列数
	}

	matrixChainMultiplication()
	fmt.Println(m[1][n])
}

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;
}

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;
}