【CUGBACM15级BC第11场 B】hdu 5055 Bob and math problem

Bob and math problem

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 1481    Accepted Submission(s): 552

Problem Description

Recently, Bob has been thinking about a math problem.
There are N Digits, each digit is between 0 and 9. You need to use this N Digits to constitute an Integer.
This Integer needs to satisfy the following conditions:

• 1. must be an odd Integer.
  
• 2. there is no leading zero.
  
• 3. find the biggest one which is satisfied 1, 2.

Example: 
There are three Digits: 0, 1, 3. It can constitute six number of Integers. Only "301", "103" is legal, while "130", "310", "013", "031" is illegal. The biggest one of odd Integer is "301".

 

Input

There are multiple test cases. Please process till EOF.
Each case starts with a line containing an integer N ( 1 <= N <= 100 ).
The second line contains N Digits which indicate the digit a1,a2,a3,⋯,an.(0≤ai≤9).

 

Output

The output of each test case of a line. If you can constitute an Integer which is satisfied above conditions, please output the biggest one. Otherwise, output "-1" instead.

 

Sample Input

30 1 335 4 232 4 6

 

Sample Output

301425-1

 

  题意：给你n个0~9的数字，问你这些数字组合成的数中满足1：为奇数 2：没有前导零的最大数

  思路：直接模拟即可。  最后一位取最小的奇数，第一位取最大的非零数，中间的数就从大到小取了

///AC代码

#include <iostream>#include <set>#include <map>#include <stack>#include <cmath>#include <queue>#include <cstdio>#include <bitset>#include <string>#include <vector>#include <iomanip>#include <cstring>#include <algorithm>#include <functional>#define PI acos(-1)#define eps 1e-8#define inf 0x3f3f3f3f#define debug(x) cout<<"---"<<x<<"---"<<endltypedef long long ll;using namespace std;int a[110];int main(){    int n;    while (scanf("%d", &n) != EOF)    {        memset(a, -1, sizeof(a));        for (int i = 0; i < n; i++)        {            scanf("%d", &a[i]);        }        if (n == 1)        {            if (a[0] % 2 == 1)            {                printf("%d\n", a[0]);                continue;            }            else            {                printf("-1\n");                continue;            }        }        int minn = inf, minn_id;        for (int i = 0; i < n; i++)        {            if (a[i] % 2 == 1 && a[i] < minn)            {                minn = a[i];                minn_id = i;            }        }        int maxx = -inf, maxx_id;        for (int i = 0; i < n; i++)        {            if (a[i] > maxx && i != minn_id && a[i] != 0)            {                maxx = a[i];                maxx_id = i;            }        }        if (maxx == -inf || minn == inf)        {            printf("-1\n");            continue;        }        a[minn_id] = -1;        a[maxx_id] = -1;        sort(a, a + n);        printf("%d", maxx);        for (int i = n - 1; i >= 2; i--)        {            printf("%d", a[i]);        }        printf("%d\n", minn);    }    return 0;}