solve3N+1Problum.c

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

void input(int *i, int *j);
int solveIJ3NPlus1MaxCycleLengthProblem(int i, int j);
int solve3NPLus1Problem(int n);

int main()
{
	while(1){
		int i, j;
		input(&i, &j);
		
		int maxCycleLength = solveIJ3NPlus1MaxCycleLengthProblem(i, j);
		printf("maxCycleLength = %d\n", maxCycleLength);
		
		system("pause");
	}
	return 0;
}

void input(int *i, int *j)
{
	scanf("%d%d", i, j);
	if(*j < *i){
		int temp = *i;
		*i = *j;
		*j = temp;
	}
}


int solve3NPLus1Problem(int n)
{
	long long int longLongIntN = n;
	int cycleLength = 1;
	while(1){
		if(longLongIntN==1){
			return cycleLength;
		}else if(longLongIntN%2==1){
			longLongIntN = longLongIntN * 3 + 1;
		}else
		{
			longLongIntN = longLongIntN / 2;
		}
		cycleLength++;
	}
}


int solveIJ3NPlus1MaxCycleLengthProblem(int i, int j)
{
	int n;
	int maxCycleLength = 1;
	for(n=i;n<=j;n++){
		int cycleLength = solve3NPLus1Problem(n);
		if(maxCycleLength < cycleLength)
		{
			maxCycleLength = cycleLength;
		}
	}
	return maxCycleLength;
}