Question

我试图解决EulerProblem8 https://projecteuler.net/problem=8而我只是没有得到它，我做错了什么？我之前尝试过使用一个文件和ArrayList，但是无法将其拉下来......什么是错的，subtsrings，循环，* = ...我不知道该怎么办？

package largestproductinaseries_ep8;

//The four adjacent digits in the 1000-digit number 
//that have the greatest product are 9 × 9 × 8 × 9 = 5832.
//Find the thirteen adjacent digits in the 1000-digit number 
//that have the greatest product. What is the value of this product?

public class LargestProductInASeries_EP8 {
    public static void main(String[] args){
    String bigNum = "73167176531330624919225119674426574742355349194934" +
                    "96983520312774506326239578318016984801869478851843" +
                    "85861560789112949495459501737958331952853208805511" +
                    "12540698747158523863050715693290963295227443043557" +
                    "66896648950445244523161731856403098711121722383113" +
                    "62229893423380308135336276614282806444486645238749" +
                    "30358907296290491560440772390713810515859307960866" +
                    "70172427121883998797908792274921901699720888093776" +
                    "65727333001053367881220235421809751254540594752243" +
                    "52584907711670556013604839586446706324415722155397" +
                    "53697817977846174064955149290862569321978468622482" +
                    "83972241375657056057490261407972968652414535100474" +
                    "82166370484403199890008895243450658541227588666881" +
                    "16427171479924442928230863465674813919123162824586" +
                    "17866458359124566529476545682848912883142607690042" +
                    "24219022671055626321111109370544217506941658960408" +
                    "07198403850962455444362981230987879927244284909188" +
                    "84580156166097919133875499200524063689912560717606" +
                    "05886116467109405077541002256983155200055935729725" +
                    "71636269561882670428252483600823257530420752963450";


    int a           = 0;
    String peace    = "";
    String onePeace = "";
    int onePeaceNum = 0;
    int multi = 1;
    int maxMulti = 0;
    while(a<bigNum.length()-12){
        peace = bigNum.substring(a, a+13);
        if(!peace.contains("0")){
            for(int i = 12; i>=0; i--){
                onePeace = peace.substring(i, i+1);
                onePeaceNum = Integer.parseInt(onePeace);
                multi *= onePeaceNum;
                if(multi>maxMulti){
                    maxMulti = multi;
                }
            }
            multi = 1;
        }
        a++;
    }  
    System.out.println(maxMulti);
}
}
//23514624000 this is Euler answer
// 2091059712 this is my output

Answer 1

你的实现有问题，你永远不会重置mult值，所以你继续倍增，你不会在13个数字后停止。你的代码应该是：

            if (mult > maxMult) {
                maxMult = mult;
                mult = 1;
            } else {
                mult = 1;
            }

如何使用ArrayList和subList计算n个ad jecent数字的乘积？

1 个答案: