Largest Number

Change-Id: I0783dca28bda6c6c36e414e204608183597fc800

Author: applewjg

LargestNumber.java

@@ -0,0 +1,64 @@
+/*
+ Author:     King, [email protected]
+ Date:       Jan 13, 2015
+ Problem:    ZigZag Conversion
+ Difficulty: Medium
+ Source:     https://oj.leetcode.com/problems/largest-number/
+ Notes:
+ 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.
+
+ Solution: ...
+ */
+
+public class Solution {
+    public String largestNumber_1(int[] num) {
+        int size = num.length;
+        if (size <= 0) return new String();
+        if (size == 1) return String.valueOf(num[0]);
+        Comparator<Integer> comp =  new Comparator<Integer>(){  
+            public int compare(Integer a,  Integer b) { 
+                    String aa = ""+a+b;
+                    String bb = ""+b+a;
+                    return bb.compareTo(aa);
+            }  
+        };
+        Integer[] in = new Integer[size];
+        for (int i = 0; i < size; ++i)
+            in[i] = Integer.valueOf(num[i]);
+        Arrays.sort(in, comp);
+        StringBuffer res = new StringBuffer();
+        int i = 0;
+        while ((i < in.length - 1) && (in[i] == 0)) ++i;
+        while (i < in.length) res.append(in[i++]);
+        return res.toString();
+    }
+    public String largestNumber_2(int[] num) {
+        int size = num.length;
+        if (size <= 0) return new String();
+        String[] in = new String[size];
+        for (int i = 0; i < size; ++i)
+            in[i] = String.valueOf(num[i]);
+        return foo(in);
+    }
+    public String foo(String[] in) {
+        if (in.length == 0) return new String();
+        if (in.length == 1) return in[0];
+        StringBuffer res = new StringBuffer();
+        Comparator<String> comp =  new Comparator<String>(){  
+            public int compare(String a,  String b) { 
+                    String aa = a+b;
+                    String bb = b+a;
+                    return bb.compareTo(aa);
+            }  
+        };
+        Arrays.sort(in, comp);
+        int i = 0;
+        while ((i < in.length - 1) && (in[i].compareTo("0") == 0)) ++i;
+        while (i < in.length) res.append(in[i++]);
+        return res.toString();
+    }
+}