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POCan I make this C++ code faster without making it much more complex?
 

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  1. POCan I make this C++ code faster without making it much more complex?
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    <p>here's a problem I've solved from a programming problem website(codechef.com in case anyone doesn't want to see this solution before trying themselves). This solved the problem in about 5.43 seconds with the test data, others have solved this same problem with the same test data in 0.14 seconds but with much more complex code. Can anyone point out specific areas of my code where I am losing performance? I'm still learning C++ so I know there are a million ways I could solve this problem, but I'd like to know if I can improve my own solution with some subtle changes rather than rewrite the whole thing. Or if there are any relatively simple solutions which are comparable in length but would perform better than mine I'd be interested to see them also.</p> <p>Please keep in mind I'm learning C++ so my goal here is to improve the code I understand, not just to be given a perfect solution.</p> <p>Thanks</p> <h1>Problem:</h1> <p>The purpose of this problem is to verify whether the method you are using to read input data is sufficiently fast to handle problems branded with the enormous Input/Output warning. You are expected to be able to process at least 2.5MB of input data per second at runtime. Time limit to process the test data is 8 seconds.</p> <p>The input begins with two positive integers n k (n, k&lt;=10^7). The next n lines of input contain one positive integer ti, not greater than 10^9, each. Output</p> <p>Write a single integer to output, denoting how many integers ti are divisible by k. Example</p> <h1>Input:</h1> <p>7 3<br> 1<br> 51<br> 966369<br> 7<br> 9<br> 999996<br> 11 </p> <h1>Output:</h1> <p>4 </p> <h1>Solution:</h1> <pre><code>#include &lt;iostream&gt; #include &lt;stdio.h&gt; using namespace std; int main(){ //n is number of integers to perform calculation on //k is the divisor //inputnum is the number to be divided by k //total is the total number of inputnums divisible by k int n,k,inputnum,total; //initialize total to zero total=0; //read in n and k from stdin scanf("%i%i",&amp;n,&amp;k); //loop n times and if k divides into n, increment total for (n; n&gt;0; n--) { scanf("%i",&amp;inputnum); if(inputnum % k==0) total += 1; } //output value of total printf("%i",total); return 0; } </code></pre>
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    1. USMartijn Pieters
    1. USconorgriffin
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      1. POCan I make this C++ code faster without making it much more complex?
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      1. VTUpMod
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    1. COYou should mention the name of the website in the title so that other people can avoid seeing your solution if they haven't done that one yet. I'm guessing project Euler?
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    2. COSounds a bit too easy for project-euler
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    3. CO@Draemon @tur1ng it's from codechef.com, I added the website name to the first paragraph. It is an easy problem alright, but I'm just curious about how to optimize my code.
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