The 3n + 1 problemTime Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 46560 Accepted Submission(s): 16761 http://acm.hdu.edu.cn/showproblem.php?pid=1032 Problem Description Problems in Computer Science are often classified as belonging to a certain class of problems (e.g., NP, Unsolvable, Recursive). In this problem you will be analyzing a property of an algorithm whose classification is not known for all possible inputs. Input The input will consist of a series of pairs of integers i and j, one pair of integers per line. All integers will be less than 1,000,000 and greater than 0. Output For each pair of input integers i and j you should output i, j, and the maximum cycle length for integers between and including i and j. These three numbers should be separated by at least one space with all three numbers on one line and with one line of output for each line of input. The integers i and j must appear in the output in the same order in which they appeared in the input and should be followed by the maximum cycle length (on the same line). Sample Input 1 10 100 200 201 210 900 1000
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Sample Output 1 10 20 100 200 125 201 210 89 900 1000 174 |
代码:
#include<iostream>
#include<cstring>
#include<cmath>
#include<iomanip>
#include<algorithm>
#include<cstdio>
#define inf 0x3f3f3f3f
using namespace std;
int main()
{
int n,m;
while(cin>>n>>m)
{
long long maxx=0;
int flag=0;
if(n>m)
{
swap(n,m);
flag=1;
}
for(int i=n;i<=m;i++)
{
long long sum=1;
long long j=i;
while(j!=1)
{
if(j&1)
j=3*j+1;
else
j/=2;
sum++;
}
//cout<<i<<":"<<sum<<endl;
//if(maxx<sum)
//{
//maxx=sum;
//flag=i;
//}
maxx=max(maxx,sum);
}
if(!flag)
cout<<n<<" "<<m<<" "<<maxx<<endl;
else
cout<<m<<" "<<n<<" "<<maxx<<endl;
}
return 0;
}