HDU 5055 - Bob and math problem（贪心）

题意

思路

代码

#include <cstdio>

#include <stack>

#include <set>

#include <iostream>

#include <string>

#include <vector>

#include <queue>

#include <functional>

#include <cstring>

#include <algorithm>

#include <cctype>

#include <ctime>

#include <cstdlib>

#include <fstream>

#include <string>

#include <sstream>

#include <map>

#include <cmath>

#define LL long long

#define lowbit(x) ((x) & (-x))

#define MP(a, b) make_pair(a, b)

#define MS(arr, num) memset(arr, num, sizeof(arr))

#define PB push_back

#define F first

#define S second

#define ROP freopen("input.txt", "r", stdin);

#define BitCount(x) __builtin_popcount(x)

const double PI = acos(-1.0);

const int INF = 0x3f3f3f3f;

using namespace std;

const int MAXN = 1e4 + 100;

const int MAXN2 = 1e6 + 5;

const int MOD = 20071027;

typedef pair<int, int> pii;

typedef vector<int>::iterator viti;

typedef vector<pii>::iterator vitii;

int ans[MAXN], dic[] = {1,3,5,7,9}, num[10];

int main()

{

//ROP;

int n, i, j;

while (~scanf("%d", &n))

{

int pos = 1, temp;

MS(num, 0);

MS(ans, 0);

for (i = 0; i < n; i++)

    {

scanf("%d", &temp);

num[temp]++;

}

bool flag = false;

for (i = 0; i < 5; i++)

    {

if (num[dic[i]])

{

ans[n] = dic[i];

flag = true;

num[dic[i]]--;

break;

}

}

if (!flag)

    {

printf("-1\n");

continue;

}

else

    {

for (i = 9; i >= 1; i--)

for (j = 0; j < num[i]; j++) ans[pos++] = i;

if (pos == 1 && n != 1)

{

    printf("-1\n");

    continue;

}

}

for (i = 1; i <= n; i++) printf("%d", ans[i]);

puts("");

}

return 0;

}