调试此代码以查找1000位数字中13个相邻数字的最高乘积

Question

我试图创建一个C++程序来解决Project Euler的第8个问题。但是，我的程序没有输出正确的答案。我试着追踪它，但找不到我的逻辑错误。

Project Euler的第八个问题是关于在一个有1000个数字的数字中找到十三个相邻数字的最高乘积的值。我的代码输出9223372019204292608作为答案。正确答案是我相信是23514624000。我的代码如下：

#include <iostream>
#include <cassert>
using namespace std;
int main() {
//Declare input number as a string. Declare variables
string input = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
char initialArray[1000];
int finalArray[1000];
long products[987];
long highestProduct = 0L;
//Divide input string into an array of single characters
for(int i = 0; i < 1000 ; i++){
initialArray[i] = input.at(i);
}
//Translate the array of characters into an array of single-digit integers
for(int i = 0; i < 1000 ; i++){
finalArray[i] = input.at(i) - '0';
}
//Initialize each element in the products array to 1
for (int i = 0; i < 100 ; i++){
products[i] = 1L;
}

//Perform multiplications
for(int i = 0; i < 987; i++){
for( int j = 0; j < 13; j++){
products[i] = products[i] * finalArray[j+i];
}
}
for(int i = 0; i < 987; i++){
if (products[i] > highestProduct){
highestProduct = products[i];
}
}
cout << "The highest product of 13 adjacent digits from the input is: " <<                            highestProduct << endl;
return 0;
}
//Correct answer is supposed to be 23514624000

Answer 1

您没有初始化所有products数组。理想情况下，您根本不应该单独初始化它们。

//Perform multiplications
for(int i = 0; i < 987; i++)
{
products[i] = 1L;  // initialize
for( int j = 0; j < 13; j++)
{
products[i] = products[i] * finalArray[j+i];
}
}

这样，初始化所有元素就不会出错。

Answer 2

查看此处：

//将products数组中的每个元素初始化为1
for(int i=0；i<100；i++(｛

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另外请注意，您可以在每一步使用产品更新的唯一循环数组，如下所示：

product = (product / finalArray[i - 13]) * finalArray[i]