【CODEFORCES】 C. Hacking Cypher

C. Hacking Cypher
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Polycarpus participates in a competition for hacking into a new secure messenger. He's almost won.

Having carefully studied the interaction protocol, Polycarpus came to the conclusion that the secret key can be obtained if he properly cuts the public key of the application into two parts. The public key is a long integer which may consist of even a million digits!

Polycarpus needs to find such a way to cut the public key into two nonempty parts, that the first (left) part is divisible by a as a separate number, and the second (right) part is divisible by b as a separate number. Both parts should be positive integers that have no leading zeros. Polycarpus knows values a and b.

Help Polycarpus and find any suitable method to cut the public key.

Input

The first line of the input contains the public key of the messenger — an integer without leading zeroes, its length is in range from 1 to106 digits. The second line contains a pair of space-separated positive integers ab (1 ≤ a, b ≤ 108).

Output

In the first line print "YES" (without the quotes), if the method satisfying conditions above exists. In this case, next print two lines — the left and right parts after the cut. These two parts, being concatenated, must be exactly identical to the public key. The left part must be divisible by a, and the right part must be divisible by b. The two parts must be positive integers having no leading zeros. If there are several answers, print any of them.

If there is no answer, print in a single line "NO" (without the quotes).

Sample test(s)
input
116401024
97 1024
output
YES
11640
1024
input
284254589153928171911281811000
1009 1000
output
YES
2842545891539
28171911281811000
input
120
12 1
output
NO
题解:这一题首先是想到的是暴力,用两个数组记录前缀mod a和后缀mod b的值,反正只需要来回推一遍,可以承受。结果后来超时了几次,我还以为是算法出的问题,结果后来发现是因为写程序的时候不严谨,long long 和int 混用导致程序在类型转换的时候花去了大量时间,这个以后要注意。
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cstdlib>

using namespace std;

long long a,b,pre[1000005],suf[1000005];
char s[1000005];

void solve(char *s)
{
    //pre
    long long l=strlen(s),ten=1,k;
    memset(pre,0,sizeof(pre));
    memset(suf,0,sizeof(suf));
    for (int i=1;i<=l;i++)
        pre[i]=((pre[i-1]*10)%a+(s[i-1]-48)%a)%a;
    for (int i=l;i>=1;i--)
    {
        k=s[i-1]-48;
        k=((k%b)*(ten%b))%b;
        suf[i]=(suf[i+1]%b+k)%b;
        ten=((ten%b)*(10%b))%b;
    }
}

int main()
{
    scanf("%s",s);
    scanf("%I64d%I64d",&a,&b);
    solve(s);
    int l=strlen(s);
    for (int i=1;i<=l-1;i++) if (s[i]!='0' && pre[i]==0 && suf[i+1]==0)
    {
        printf("YES\n");
        for (int j=0;j<=i-1;j++) printf("%c",s[j]);
        printf("\n");
        for (int j=i;j<l;j++) printf("%c",s[j]);
        return 0;
    }
    printf("NO\n");
    return 0;
}


### Codeforces Div.2 比赛难度介绍 Codeforces Div.2 比赛主要面向的是具有基础编程技能到中级水平的选手。这类比赛通常吸引了大量来自全球不同背景的参赛者,包括大学生、高中生以及一些专业人士。 #### 参加资格 为了参加 Div.2 比赛,选手的评级应不超过 2099 分[^1]。这意味着该级别的竞赛适合那些已经掌握了一定算法知识并能熟练运用至少一种编程语言的人群参与挑战。 #### 题目设置 每场 Div.2 比赛一般会提供五至七道题目,在某些特殊情况下可能会更多或更少。这些题目按照预计解决难度递增排列: - **简单题(A, B 类型)**: 主要测试基本的数据结构操作和常见算法的应用能力;例如数组处理、字符串匹配等。 - **中等偏难题(C, D 类型)**: 开始涉及较为复杂的逻辑推理能力和特定领域内的高级技巧;比如图论中的最短路径计算或是动态规划入门应用实例。 - **高难度题(E及以上类型)**: 对于这些问题,则更加侧重考察深入理解复杂概念的能力,并能够灵活组合多种方法来解决问题;这往往需要较强的创造力与丰富的实践经验支持。 对于新手来说,建议先专注于理解和练习前几类较容易的问题,随着经验积累和技术提升再逐步尝试更高层次的任务。 ```cpp // 示例代码展示如何判断一个数是否为偶数 #include <iostream> using namespace std; bool is_even(int num){ return num % 2 == 0; } int main(){ int number = 4; // 测试数据 if(is_even(number)){ cout << "The given number is even."; }else{ cout << "The given number is odd."; } } ```
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