hdu 5055(贪心)

来源：互联网发布：网络管理从入门到精通编辑：程序博客网时间：2024/06/13 11:52

题意：给你N个数，每个数的取值范围为[0,9]，求这N个数组成的最大奇数，且该奇数不能有前导零。

解题思路：将偶数和奇数分开，然后分别按从小到大排序，将最小的奇数先拿出来，把剩余的数从大到小排好，最后再将最小的奇数放进去。

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int maxn = 105;int n,a,oddNum,evenNum;char odd[maxn],even[maxn],res[maxn];bool cmp(int a,int b){return a > b;}int main(){while(scanf("%d",&n)!=EOF){evenNum = oddNum = 0;for(int i = 1; i <= n; i++){scanf("%d",&a);if(a % 2 == 0)even[evenNum++] = '0' + a;else odd[oddNum++] = '0' + a;}if(oddNum == 0){printf("-1\n");continue;}sort(odd,odd+oddNum,cmp);sort(even,even+evenNum,cmp);int l = 0, r = 0, cnt = 0;while(l < oddNum - 1 && r < evenNum){if(odd[l] > even[r]){res[cnt++] = odd[l];l++;}else{res[cnt++] = even[r];r++;}}while(r < evenNum){res[cnt++] = even[r];r++;}while(l < oddNum){res[cnt++] = odd[l];l++;}res[cnt] = '\0';if(res[0] == '0') printf("-1\n");else printf("%s\n",res);}return 0;}

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