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())
}

Python: n = int(input())
p = [item for sublist in [[int(input().split()[1])] if i != 0 else list(map(int, input().split())) for i in range(n)] for item in sublist]

def memolize(f):
    cache = {}

    def helper(x, y):
        if (x, y) not in cache:
            cache[(x, y)] = f(x, y)
        return cache[(x, y)]
    return helper

@memolize
def calcMatrixOrder(i, j):
    if i == j :
        return 0
    return min([calcMatrixOrder(i, k) + calcMatrixOrder(k + 1, j) + p[i]*p[k+1]*p[j + 1] for k in range(i, j)])

print(calcMatrixOrder(0, n - 1))

Python: import sys
input = lambda: sys.stdin.readline().rstrip() 

def resolve():
    n = int(input())
    M = [list(map(int, input().split())) for _ in range(n)]

    # dp[i][j]: [i, j)の最小乗算数
    dp = [[0]*(n+1) for _ in range(n)]

    # 幅
    for i in range(2, n+1):
        # 開始位置
        for j in range(n-i+1):
            tmp = []
            # 切れ目
            for k in range(j+1, j+i):
                tmp.append(M[j][0]*M[k][0]*M[j+i-1][1]+dp[j][k]+dp[k][j+i])
            dp[j][j+i] = min(tmp)

    print(dp[0][n])

if __name__ == '__main__':
    resolve()

Python: # -*- coding: utf-8 -*-
N = int(input())
p = [0 for _ in range(N+1)]

p[0], p[1] = map(int, input().split())
for n in range(2, N+1):
    p[n] = list(map(int, input().split()))[1]

M = [[0]*(N+1) for _ in range(N+1)]

for n in range(N+1):
    M[n][n] = 0

for l in range(2, N+1):
    for i in range(1, N-l+2):
        j = i + l - 1
        M[i][j] = float("inf")
        for k in range(i, j):
            M[i][j] = min(M[i][j], M[i][k] + M[k+1][j] + p[i-1]*p[k]*p[j])

print(M[1][N])

Python: # https://onlinejudge.u-aizu.ac.jp/courses/lesson/1/ALDS1/10/ALDS1_10_B
# 普通に難しい
# アイデアは写真の解説を参照

# データの入力
N = int(input())

for i in range(N):
    if i == 0:
        P = list(map(int, input().split()))
        continue
    P.append(int(input().split()[1]))

# dpテーブルの用意 minを取るときはinf埋めしておくと処理が楽になるしバグが見つかりやすい
INF = 2**32-1
dp = [[INF]*N for _ in range(N)]

# dpテーブルの初期化
# 対角成分0
for ij in range(N):
    dp[ij][ij] = 0

# dpの更新 どう更新しているのか、なんでこう更新するのかは写真を参照
for l in range(1, N):  # lは対角成分からいくつ離れているか (なん個行列をかけるかという解釈も可)
    for i in range(N):
        j = i+l
        if j >= N:
            continue
        for k in range(i, j):  # 最小値探索
            dp[i][j] = min(dp[i][k] + dp[k+1][j] +
                           P[i] * P[k+1] * P[j+1], dp[i][j])
print(dp[0][-1])

Python: import sys
def input():
    return sys.stdin.readline()[:-1]
n = int(input())
A = [list(map(int, input().split())) for _ in range(n)]

p = [A[0][0]] + [A[i][1] for i in range(n)]
m = [[0 for i in range(n+1)] for j in range(n+1)]

for l in range(2,n+1):
    for i in range(1,n-l+1+1):
        j = i + l - 1
        for k in range(i,j):
            x = m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]
            if not 0<m[i][j]<=x:
                m[i][j] = x
print(m[1][n])

Python: #!/usr/bin/env python3
# -*- coding: utf-8 -*-

import sys
import re
import math
import collections
import itertools
import functools
import logging

logging.basicConfig(level=logging.DEBUG, format="DBG: %(message)s")

def dbg(msg, *args, **kwargs):
    logging.debug(msg, *args, **kwargs)

Mat = collections.namedtuple("Mat", "r c")

def mat_mul(ms):
    return Mat(ms[0].r, ms[-1].c)

def cost(m1, m2):
    return m1.r * m1.c * m2.c

def solve(n, ms):
    if n == 1: return 0

    dp = {}
    for i in range(n):
        dp[(i,i)] = 0

    for l in range(2, n+1):
        for i in range(n-l+1):
            #cost_min = math.inf
            cost_min = float("inf")
            for j in range(l-1):
                dbg("l, i, j: %d %d %d", l, i, j)
                m_lhs = mat_mul(ms[i:i+j+1])
                m_rhs = mat_mul(ms[i+j+1:i+l])
                dbg("m_lhs, m_rhs: %r %r", m_lhs, m_rhs)
                cost_lhs = dp[(i,i+j)]
                cost_rhs = dp[(i+j+1,i+l-1)]
                dbg("cost_lhs, cost_rhs: %d %d", cost_lhs, cost_rhs)
                cost_mul = cost(m_lhs, m_rhs)
                dbg("cost_mul: %d", cost_mul)
                cost_now = cost_mul + cost_lhs + cost_rhs
                dbg("cost_now: %d", cost_now)
                if cost_min > cost_now:
                    cost_min = cost_now
            dp[(i,i+l-1)] = cost_min

    dbg(dp)
    return dp[(0,n-1)]

def main():
    n = int(input())

    ms = []
    for _ in range(n):
        r,c = map(int, input().split())
        ms.append(Mat(r,c))

    print(solve(n, ms))

if __name__ == "__main__": main()

Python: def s():
 n=int(input())+1
 e=[input().split()for _  in[0]*~-n]
 p=[int(e[0][0])]+list(int(x[1])for x in e)
 m=[[0]*n for _ in[0]*n]
 for i in range(n):
  for r in range(n-i-1):
   c=r+i+1
   for j in range(r+1,c):
    x=m[r][j]+m[j][c]+p[r]*p[j]*p[c]
    if not 0<m[r][c]<x:m[r][c]=x
 print(m[r][c])
if'__main__'==__name__:s()

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys


def mat_mul_opt(_mat_info):
    r, c = map(int, _mat_info[0])
    rc_info.extend([r, c])
    for each in _mat_info[1:]:
        rc_info.append(int(each[1]))

    for l in range(2, mat_num + 1):
        for i in range(1, mat_num - l + 2):
            j = i + l - 1
            ans[i][j] = 1e7
            for k in range(i, j):
                ans[i][j] = min(ans[i][j], ans[i][k] + ans[k + 1][j] +
                                rc_info[i - 1] * rc_info[k] * rc_info[j])

    return ans[1][mat_num]


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    mat_num = int(_input[0])
    mat_info = tuple(map(lambda x: x.split(), _input[1:]))

    rc_info = []
    ans = [[0] * (mat_num + 1) for _ in range(mat_num + 1)]
    print(mat_mul_opt(mat_info))

Python: n = int(input())
p = [None] * (n+1)# i番目の列数 = i+1番目の行数
for i in range(n):
  p[i], p[i+1] = map(int, input().split())

INF = 10**18
m = [[None] * n for _ in range(n)]
for i in range(n):
  m[i][i] = 0
  
for l in range(2,n+1):# 行列の連鎖数
  for i in range(n-l+1):
    j = i + l - 1# [i, j]の範囲の計算の最小コストを考える
    m[i][j] = INF
    for k in range(i,j):
      m[i][j] = min(m[i][j], m[i][k]+m[k+1][j] + p[i-1]*p[k]*p[j])

print(m[0][n-1])