OJ Board

Code: Select all

if ((i & 1) == 1)
    i = i * 3 + 1;
else
    i >>= 1;

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/* program to find the maximum cycle count for the solution of the 3n+1 
 * problem for a series of numbers defined by bounds as entered from 
 * stdin, inclusive.*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define TESTING 0
#define DEBUG 0
#define MAXNUM 1000
#define BASECOUNT 1

int processNumber (int num);

int main(void) {

	int a[MAXNUM], b[MAXNUM], i, j, n;		/*upper and lower bounds and current number working on*/
	int count, maxcount, entrycount = 0;		/*cycle count and max count for this dataset*/
	char s[17];					/*holds the string read in from stdin*/

	while((fgets(s, 17, stdin)) != (char *)0){
		a[entrycount] = atoi(strtok(s, " "));	/*take the string, tokenise it, then convert to int*/
		b[entrycount] = atoi(strtok(NULL, " "));
		entrycount++;
	}
	entrycount--;					/*don't want the EOF as our final entry*/
	
	int m;		/*counter*/	
	for (m=0;m<=entrycount;m++) {
		maxcount = 0;

		if (b[m]>=a[m]) {
			i = a[m];
			j = b[m];
			if (TESTING) printf("a=%d, b=%d, i=%d, j=%d\n", a[m], b[m], i, j);
			for (i;i<=j;i++){
				count = BASECOUNT;
				n = i;
				while (n>1) {
					++count;
					n = processNumber(n);
				}
				if (TESTING) printf("count for number %d is %d\n", i, count);
				if (count > maxcount)
					maxcount = count;
			}
		}
		else {
			j = a[m];
			i = b[m];
			if (TESTING) printf("a=%d, b=%d, i=%d, j=%d\n", a[m], b[m], i, j);
			for (i;i<=j;i++){
				count = BASECOUNT;
				n = i;
				while (n>1) {
					++count;
					n = processNumber(n);
				}
				if (TESTING) printf("count for number %d is %d\n", i, count);
				if (TESTING) break;
				if (count > maxcount)
					maxcount = count;
			}
		}
		printf("%d %d %d\n", a[m], b[m], maxcount);
	}
	return 0;
}

int processNumber(int num) {
	
	if (DEBUG) printf("***Entered processNumber, num is %d\n", num);
	if (num % 2 == 0) {
		num = num / 2;
	}
	else {
		num = (3 * num) +1;
	}
	return num;
}

Code: Select all

#include <stdio.h>

int Q(int n)
{
   int cyclelength=1;

   while(n>1)
   {
     if((n%2)==1) {
        n=3*n+1;
     }
     else n = n/2;
        cyclelength++;
   }
   return cyclelength;
}

int main()
{
    int  a, b, i, t, max_clength;

    while(scanf("%d %d", &a, &b)==2) {
       printf("%d %d ", a, b);
       if(a>b){
         t=a; a=b; b=t;
       }
       max_clength=0;
       for(i=a; i<=b; i++){
           t = Q( i );
           if(t > max_clength)  max_clength=t;
       }
       printf("%d\n", max_clength);
    }
}

Code: Select all

#include <stdio.h>

#define TABLE_SIZE 1000000
int calculated [TABLE_SIZE];

/* -------------------------------------------------------------------------- */
/*  Recieves input from the user, spits back output                           */
/* -------------------------------------------------------------------------- */
int main (int argc, const char * args[]) {

	int a, b, low, high, max;

	while(!feof(stdin)) {
		scanf("%d %d", &low, &high);
		a = low, b = high;
		
		/* ------------------------------------------------------------------ */
		/*  Perform some quick checks to prevent runtime errors.              */
		/* ------------------------------------------------------------------ */
		if(low > high) {
			int temp = high;
			high = low;
			low = temp;
		}
		
		max = cycleLength(low);
		
		/* ------------------------------------------------------------------ */
		/*  Now start scanning through the range to find the maximum.		  */
		/* ------------------------------------------------------------------ */
		int counter;
		for(counter = (low+1); counter <= high; counter++) {
			calculated[counter] = cycleLength(counter);
			
			if(calculated[counter] > max)
				max = calculated[counter];
		}
		
		printf("%d %d %d\n", a, b, max);
	}
	
    return 0;
}

/* -------------------------------------------------------------------------- */
/*  Determines the cycle length for a given integer.						  */
/*																			  */
/*  The value is looked up in each instance to see if it has already been	  */
/*  calculated (in order to save processing time). If the value has not been  */
/*  precalculated, it is save once it is calculated.						  */
/* -------------------------------------------------------------------------- */
int cycleLength(unsigned int num) {

	if(num < TABLE_SIZE)
		if(calculated[num] != 0)
			return calculated[num];

	if(num != 1)
		return (num&1) ? 1 + cycleLength(num*3 + 1) : 1 + cycleLength(num/2);
	
	else return 1;
}

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Scanner getInput=new Scanner(new BufferedInputStream(System.in));

Code: Select all

# include <stdio.h>

int main()
{
	
	int i=0,one, two, max=0;
	scanf("%d %d",&one,&two);
	int j=one;
	while(j<=two)
	{
		one=j;
		i=0;
		while(one!=1)
		{
			if(one%2==0)
			{
				one=one/2;
				i++;
			}
			else if(one%2==1)
			{
				one=3*one+1;
				i++;
			}
		}
		i++;/*for one=1*/
		if(max>i)
			max=max;
		else
			max=i;
		j++;
	}
	printf(" %d",max);
	return 0;
}

Code: Select all

# include <stdio.h>

int main()
{
	
	int i=0,one, two, max=0;
	scanf("%d %d",&one,&two);
	int j=one;
	while(j<=two)
	{
		one=j;
		i=0;
		while(one!=1)
		{
			if(one%2==0)
			{
				one=one/2;
				i++;
			}
			else if(one%2==1)
			{
				one=3*one+1;
				i++;
			}
		}
		i++;/*for one=1*/
		if(max>i)
			max=max;
		else
			max=i;
		j++;
	}
	printf(" %d",max);
	return 0;
}