描述
Given a list of non negative integers, arrange them such that they form the largest number.
Example 1:
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| Input: [10,2] Output: "210"
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Example 2:
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| Input: [3,30,34,5,9] Output: "9534330"
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Note: The result may be very large, so you need to return a string instead of an integer.
分析
又是一道自定义排序算法的问题。有两个需要注意的地方,1,虽然这里是按照大小排序,数字更大的排在前面,也要考虑两个数字之间的组合情况,比如下面的测试用例:
Input:[3,30,34,5,9]
Output:”9534303”
Expected:”9534330”
如果只考虑两两的大小比较,”30” > “3”,而真实情况是 “330” > “303”,因此我们应该比较两两组合之后的字符串。
- 需要考虑 [0, 0] 这样的 corner case,对于 [0, 0] 如果不做特殊处理,会返回 “00”,而实际上我们只需要 “0”。
解决方案1(Java)
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| class Solution { public String largestNumber(int[] nums) { if (nums.length == 0) { return ""; } String[] nums2Strings = new String[nums.length]; for (int i = 0; i < nums.length; i++) { nums2Strings[i] = String.valueOf(nums[i]); } Arrays.sort(nums2Strings, new Comparator<String>() { public int compare(String s1, String s2) { String s1s2 = s1 + s2; String s2s1 = s2 + s1; return s2s1.compareTo(s1s2); } }); if (nums2Strings[0].equals("0")) { return "0"; } StringBuilder result = new StringBuilder(); for (String str: nums2Strings) { result.append(str); } return result.toString(); } }
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