488 - Triangle Wave

[Obaida]

I am sending you a code by PM you better check it.
And trace the method.

[hahahaken]

I am sending you a code by PM you better check it.
And trace the method.

Actually mine is similar to yours and I submit my code again, still time limit exceeded
Is it related to repeatedly calling the function in my program?

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Removed after AC

[Obaida]

Try it removing the function. Hope it will work.

[hahahaken]

Try it removing the function. Hope it will work.

I have already removed the function, TLE AGAIN, NO!!!
Pls take a look at my code, I think there should be something wrong.

Code: Select all

Removed after AC

[Obaida]

Those cin and cout are slow function.
Remove them and use printf and scanf.

[hahahaken]

Those cin and cout are slow function.
Remove them and use printf and scanf.

The version you sent me also uses cin and cout, it's a AC, right?
Mine is not just only exceeded for a few seconds, but at least 5 - 10s, coz I keep refreshing firefox and the status keep "running" until TLE appears.
Then, the problem is that why you use cin and cout and you got correct answer but mine got TLE?

[Obaida]

You should check it out, and i think it's possible for you.
So why it's me?

[DJWS]

Those cin and cout are slow function.
Remove them and use printf and scanf.

In this problem, you can replace "endl" with "\n" and get reasonable runtime. "endl" push a character "\n" into I/O buffer and flush the buffer immediately. Frequent flushing will take a lot of time, especially with massive I/O data.

Although "endl" is somehow slower than single "\n", "endl" is not bad at all. The advantage of "endl" is that we can ensure the I/O data printing on the screen, line by line. Even though the program crashed, we still can see all messages generated by the program before the crashing. The advantage of "endl" is helpful when debugging.

BTW, cin and cout can be faster if we set up this:

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cin.sync_with_stdio(false);
cout.sync_with_stdio(false);

Thus cin and cout are almost as fast as scanf and printf.

[hahahaken]

Finally got AC, thanks
But I want to know why the following can make my program run faster:
1. What's the difference between "endl" and "\n"?
2. What's the difference between "cin and cout" and "scanf and printf"?
3. Why "cin.sync_with_stdio(false);" and "cout.sync_with_stdio(false);" can make my program run faster?

[DJWS]

Finally got AC, thanks
But I want to know why the following can make my program run faster:
1. What's the difference between "endl" and "\n"?
2. What's the difference between "cin and cout" and "scanf and printf"?
3. Why "cin.sync_with_stdio(false);" and "cout.sync_with_stdio(false);" can make my program run faster?

They are good questions. But I cannot explain them within few words (because I am inarticulate in English). It needs deeper views about the hardware architecture and about C/C++ languages. You may google or ask others for the details.

[newton]

There would be only one test case.
You need not to handle it upto EOF.
just change
** You must avoid printing newline at the last of output.

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 while(scanf("%d",&n) ==1){
-------
-------
}
to

scanf("%d",&n);
------
------

[mrmrumman]

Why I get wrong anser with my code what is the solution?

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[b]# include <stdio.h>
int main()
{
	int cases,i,height,frequency,j;
	char line;
	while(scanf("%d",&cases)==1)
        {
		for(i=0;i<cases;i++)
		{
			scanf("%d",&height);
			scanf("%d",&frequency);
			for(int l=0;l<frequency;l++)
			{
				if(l!=0)
					printf("\n\n");
				for(j=1;j<=height;j++)
				{
					for(int k=0;k<j;k++)
						printf("%d",j);
					printf("\n");
				}
				for(j=height-1;j>=1;j--)
				{
					if(j!=height-1)
						printf("\n");
					for(int k=0;k<j;k++)
						printf("%d",j);

				}

			}
		}
	
        }
	return 0;
}[/b]

[mrmrumman]

any1 can help why I get WA?

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# include <stdio.h>
int main()
{
	int cases,i,height,frequency,j;
	
	scanf("%d",&cases);
	for(i=0;i<cases;i++)
	{
		scanf("%d",&height);
		scanf("%d",&frequency);
		for(int l=0;l<frequency;l++)
		{
			if(l!=0)
				printf("\n");
			printf("\n");
			for(j=1;j<=height;j++)
			{
				for(int k=0;k<j;k++)
					printf("%d",j);
				printf("\n");
			}
			for(j=height-1;j>=1;j--)
			{
				if(j!=height-1)
					printf("\n");
				for(int k=0;k<j;k++)
					printf("%d",j);
			}
		}
	}
 	return 0;
}

[emotional blind]

You should not print a blank line at the very beginning.

[mrmrumman]

What is the problem with code any problem with my code? Is the way I taking input is right? Please help...

Code: Select all

# include <stdio.h>
int main()
{
	int cases,i,height,frequency,j;
	
	scanf("%d",&cases);
	for(i=0;i<cases;i++)
	{
		scanf("%d",&height);
		scanf("%d",&frequency);
		for(int l=0;l<frequency;l++)
		{
			if(l!=0)
				printf("\n");
			
			for(j=1;j<=height;j++)
			{
				for(int k=0;k<j;k++)
					printf("%d",j);
				printf("\n");
			}
			for(j=height-1;j>=1;j--)
			{
				if(j!=height-1)
					printf("\n");
				for(int k=0;k<j;k++)
					printf("%d",j);
			}
			printf("\n");
		}
	}
 	return 0;
}