POJ 1426 Find The Multiple

Find The Multiple

Time Limit: 1000ms

Memory Limit: 10000KB

This problem will be judged on  PKU. Original ID: 1426
64-bit integer IO format: %lld      Java class name: Main

Special Judge

 

Given a positive integer n, write a program to find out a nonzero multiple m of n whose decimal representation contains only the digits 0 and 1. You may assume that n is not greater than 200 and there is a corresponding m containing no more than 100 decimal digits.

 

Input

The input file may contain multiple test cases. Each line contains a value of n (1 <= n <= 200). A line containing a zero terminates the input.

 

Output

For each value of n in the input print a line containing the corresponding value of m. The decimal representation of m must not contain more than 100 digits. If there are multiple solutions for a given value of n, any one of them is acceptable.

 

Sample Input

2

6

19

0

Sample Output

10

100100100100100100

111111111111111111

Source

Dhaka 2002

 

解题：搜索。题意就是输入一个数，找出它的一个倍数，该值只包含0和1

 

DFS

 1 #include <iostream>

 2 #include <cstdio>

 3 #include <cstring>

 4 #include <cmath>

 5 #include <algorithm>

 6 #include <climits>

 7 #include <vector>

 8 #include <queue>

 9 #include <cstdlib>

10 #include <string>

11 #include <set>

12 #include <stack>

13 #define LL long long

14 #define pii pair<int,int>

15 #define INF 0x3f3f3f3f

16 using namespace std;

17 int n,limit = 20;

18 unsigned LL ans;

19 bool dfs(unsigned LL cur,int step) {

20     if(step == limit) return false;

21     if(cur%n == 0) {

22         ans = cur;

23         return true;

24     }

25     if(dfs(cur*10,step+1)) return true;

26     if(dfs(cur*10+1,step+1)) return true;

27     return false;

28 }

29 int main() {

30     while(scanf("%d",&n),n) {

31         if(dfs(1,0)) printf("%I64u\n",ans);

32     }

33     return 0;

34 }

View Code

 

BFS 貌似要快那么点点

 1 #include <iostream>

 2 #include <cstdio>

 3 #include <cstring>

 4 #include <cmath>

 5 #include <algorithm>

 6 #include <climits>

 7 #include <vector>

 8 #include <queue>

 9 #include <cstdlib>

10 #include <string>

11 #include <set>

12 #include <stack>

13 #define LL long long

14 #define pii pair<int,int>

15 #define INF 0x3f3f3f3f

16 using namespace std;

17 int n,head,tail;

18 unsigned LL q[1000000];

19 unsigned LL bfs() {

20     head = tail = 0;

21     q[tail++] = 1;

22     while(head < tail) {

23         unsigned LL now = q[head++];

24         if(now%n == 0) return now;

25         unsigned LL tmp = now*10;

26         if(tmp%n == 0) return tmp;

27         q[tail++] = tmp;

28         tmp = now*10+1;

29         if(tmp%n == 0) return tmp;

30         q[tail++] = tmp;

31     }

32 }

33 int main() {

34     while(scanf("%d",&n),n) printf("%I64u\n",bfs());

35     return 0;

36 }

View Code