Given a list of non negative integers, arrange them such that they form the largest number.
For example, given [3, 30, 34, 5, 9]
, the largest formed number is 9534330
.
Note: The result may be very large, so you need to return a string instead of an integer.
Credits:
Special thanks to @ts for adding this problem and creating all test cases.
思路:这道题要求组合数字,生成的数字值最大
比如:121,12
要生成12121,而不是12112,输入的每个元素内部要有序,而组合随意。
可以将元素转化成字符串排序后拼接。但是,如果使用默认的字符串排序,则121>12,那么最后的结果会变成12112,所以,比较的方法应为:A+B > B+A ,则 A > B (加号表示字符串连接)。
class Solution { private class LargerNumberComparator implements Comparator<String> { @Override public int compare(String a, String b) { String order1 = a + b; String order2 = b + a; return order2.compareTo(order1); } } public String largestNumber(int[] nums) { // Get input integers as strings. String[] asStrs = new String[nums.length]; for (int i = 0; i < nums.length; i++) { asStrs[i] = String.valueOf(nums[i]); } // Sort strings according to custom comparator. Arrays.sort(asStrs, new LargerNumberComparator()); // If, after being sorted, the largest number is `0`, the entire number // is zero. if (asStrs[0].equals("0")) { return "0"; } // Build largest number from sorted array. String largestNumberStr = new String(); for (String numAsStr : asStrs) { largestNumberStr += numAsStr; } return largestNumberStr; } }