Create Solution.java

Author: Jerring

solution/0273.Integer to English Words/Solution.java

@@ -0,0 +1,71 @@
+class Solution {
+    private static Map<Integer, String> map;
+
+    static {
+        map = new HashMap<>();
+        map.put(1, "One");
+        map.put(2, "Two");
+        map.put(3, "Three");
+        map.put(4, "Four");
+        map.put(5, "Five");
+        map.put(6, "Six");
+        map.put(7, "Seven");
+        map.put(8, "Eight");
+        map.put(9, "Nine");
+        map.put(10, "Ten");
+        map.put(11, "Eleven");
+        map.put(12, "Twelve");
+        map.put(13, "Thirteen");
+        map.put(14, "Fourteen");
+        map.put(15, "Fifteen");
+        map.put(16, "Sixteen");
+        map.put(17, "Seventeen");
+        map.put(18, "Eighteen");
+        map.put(19, "Nineteen");
+        map.put(20, "Twenty");
+        map.put(30, "Thirty");
+        map.put(40, "Forty");
+        map.put(50, "Fifty");
+        map.put(60, "Sixty");
+        map.put(70, "Seventy");
+        map.put(80, "Eighty");
+        map.put(90, "Ninety");
+        map.put(100, "Hundred");
+        map.put(1000, "Thousand");
+        map.put(1000000, "Million");
+        map.put(1000000000, "Billion");
+    }
+
+    public String numberToWords(int num) {
+        if (num == 0) {
+            return "Zero";
+        }
+        StringBuilder sb = new StringBuilder();
+        for (int i = 1000000000; i >= 1000; i /= 1000) {
+            if (num >= i) {
+                sb.append(get3Digits(num / i)).append(' ').append(map.get(i));
+                num %= i;
+            }
+        }
+        if (num > 0) {
+            sb.append(get3Digits(num));
+        }
+        return sb.substring(1);
+    }
+
+    private String get3Digits(int num) {
+        StringBuilder sb = new StringBuilder();
+        if (num >= 100) {
+            sb.append(' ').append(map.get(num / 100)).append(' ').append(map.get(100));
+            num %= 100;
+        }
+        if (num > 0) {
+            if (num < 20 || num % 10 == 0) {
+                sb.append(' ').append(map.get(num));
+            } else {
+                sb.append(' ').append(map.get(num / 10 * 10)).append(' ').append(map.get(num % 10));
+            }
+        }
+        return sb.toString();
+    }
+}