Given a positive 32-bit integer n, you need to find the smallest 32-bit integer which has exactly the same digits existing in the integer n and is greater in value than n. If no such positive 32-bit integer exists, you need to return -1.
Example 1:
Input: 12 Output: 21
Example 2:
Input: 21 Output: -1
思路:
首先,将整型数字转换成字符串,然后利用stl提供的next_permutation()函数,求字符的全排列,对应的字符串再转换回整型,随时记录大小即可。
int nextGreaterElement2(int n) { char buf[80]; sprintf(buf, "%d", n); string s = buf; puts(s.data()); sort(s.begin(), s.end()); long long ans = INT_MAX + 1LL; do { long long tmp = atoll(s.c_str()); if (tmp > n) { ans = min(ans, tmp); } } while (next_permutation(s.begin(), s.end())); return ans <= INT_MAX ? ans : -1; }
时间: 2024-10-12 03:53:59