Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	fmt.Println(resolve(parseProblem()))
}

type matrixSize struct{ row, col int }

func calcNum(i, j matrixSize) int {
	return i.row * j.col * i.col
}

func parseProblem() (int, []matrixSize) {
	n := scanInt(sc)
	sizes := make([]matrixSize, n)
	for i := 0; i < n; i++ {
		sizes[i] = matrixSize{row: scanInt(sc), col: scanInt(sc)}
	}
	return n, sizes
}

var dp [][]int

func initDP(n int) {
	dp = make([][]int, n+1)
	for i := 0; i < len(dp); i++ {
		dp[i] = make([]int, n+1)
		for j := 0; j < len(dp[i]); j++ {
			dp[i][j] = math.MaxInt64
		}
	}
}

func resolve(n int, sizes []matrixSize) int {
	// TODO 復習
	initDP(n)
	_rec(sizes, 0, n)
	return dp[0][n]
}

func _rec(sizes []matrixSize, l, r int) int {
	if dp[l][r] != math.MaxInt64 {
		return dp[l][r]
	}
	if r-l <= 1 {
		dp[l][r] = 0
		return 0
	}
	num := math.MaxInt64
	for i := l + 1; i < r; i++ {
		v := _rec(sizes, l, i) + _rec(sizes, i, r) + calcNum(matrixSize{sizes[l].row, sizes[i].row}, matrixSize{sizes[i].row, sizes[r-1].col})
		if v < num {
			num = v
		}
	}
	dp[l][r] = num
	return dp[l][r]
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include<iostream>
#include<cmath>
#include<algorithm>
#include<string>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<iomanip>
#include<bitset>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
typedef pair<ll,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define fi first
#define sc second
#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())

const int MAX = 510000;
const int MOD = 1000000007;

ll dp[210][210];
// dp[i][j] は from i to jまで　の積の計算の最小回数

int main(){
  ll N; cin >> N;
  vector<P> a(N); rep(i,N) cin >> a[i].fi >> a[i].sc;

  // dp 初期化
  rep(i,N) rep(j,N) dp[i][j] = INF;
  rep(i,N) dp[i][i] = 0;

  repn(i,N){
    // iはいくつ離れてるか
    rep(j,N){
      // j is start
      for(ll k = j; k <= i + j; k++){
        // k が空いてた
        if(k == j){
          dp[j][j + i] = min(dp[j][j + i] , a[k].fi * a[k].sc * a[j + i].sc  + dp[j + 1][j + i]);
        }
        else if(k == i + j){
          dp[j][j + i] = min(dp[j][j + i] , dp[j][j + i - 1] + a[j].fi * a[k].fi * a[k].sc);
        }
        else{
          dp[j][j + i] = min(dp[j][j + i] ,
            dp[j][k] + a[j].fi * a[k].sc * a[j + i].sc + dp[k + 1][j + i]);
        }
      }
    }
  }

  // rep(i,N) rep(j,N) cout << i << " " << j << " " << dp[i][j] << endl;

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

C++: #include <iostream>
#include <cstdio>
#include <map>
#define MAX_NUM 100
#define INFTY 1000000000

using namespace std;

//think easy make easy

int n;//num of input


pair<int,int> MatrixChain[MAX_NUM+1];

int calc(int s,int e){//s~eの連鎖行列積の最少計算回数を出力
	int min_time  = INFTY;

	int min_tmp;
	if(s == e){
		return 0;
	}
	for(int i=s;i<e;i++){
		min_tmp = calc(s,i) + calc(i+1,e) 
			+MatrixChain[s].first*MatrixChain[i].second*MatrixChain[e].second;
		if(min_tmp < min_time)
			min_time = min_tmp;
	}
	return min_time;
}

int main(){
	scanf("%d",&n);
	int r,c;//row,column

	for(int i=0;i<n;i++){
		scanf("%d %d",&r,&c);
		MatrixChain[i] = pair<int,int>(r,c);//i:1~n-1
	}

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

	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD=1000000007;
#define INF 1LL<<30
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()

int main() {
    int n;
    cin>>n;
    int m[n+1][n+1],p[n+1];
    rep(i,n){
        cin>>p[i]>>p[i+1];
        m[i][i]=0;
    }
    m[n][n]=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]=1000000;
            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;
}

C++: #include<iostream>

#define N 101

int n;
int a[N];
int g[N][N];

using namespace std;
int main() {

    cin>>n;
    for(int i = 0; i < n; i++) cin>>a[i]>>a[i+1];
    

    int i = 1, j = 1, k = 1, min, b;
    while(1) {
        if(i == 1 && j == n+1) break;
        if(i == j) g[i][j] = 0;
        
        if(i != j) {
            min = (1<<21);
            for(int x = i; x < j; x++) {
                b = g[i][x] + g[x+1][j] + a[i-1] * a[x] * a[j];
                if(min > b) min = b;
            }
        
            g[i][j] = min;
        }
        
        i++;
        j++;
        if(j > n) {
            i = 1;
            j = ++k;
        }
    }

    cout<<g[1][n]<<endl;

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define MAX 105


int main(){
    int m[MAX][MAX];
    int p[MAX];
    int n;
    //FILE *fw=fopen("a.txt","r");
    scanf("%d",&n);
    for(int i=1;i<=n;++i){
        scanf("%d %d",&p[i],&p[i+1]);
    }
    //printf("start\n");
    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 = l+i-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]*p[k+1]*p[j+1]);
            }
        }
    }
    printf("%d\n",m[1][n]);
    return 0;
}

C++: #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++: #define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ALL(v) v.begin(), v.end()
typedef long long ll;

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

int main() { 
  int M[101][101];
  int P[100];
  rep(i,101){
    rep(j,101) M[i][j]=1e9;
  }
  
  int n;
  cin>>n;
  
  rep(i,n) cin>>P[i]>>P[i+1];
  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;
      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<iostream>
#include<algorithm>
using namespace std;

int main(){
  int n, p[101], m[101][101], i, j, k, l;
  cin >> n;
  for(i = 1;i <= n;i++){
    cin >> p[i-1] >> p[i];
  }

  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);
      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]);
      }
    }
  }

  cout << m[1][n] << endl;

  return 0;
}