Create Solution.java

Author: Jerring

solution/0483.Smallest Good Base/Solution.java

@@ -0,0 +1,39 @@
+class Solution {
+    public String smallestGoodBase(String n) {
+        long num = Long.parseLong(n);
+        for (int len = 63; len >= 2; --len) {
+            long radix = getRadix(len, num);
+            if (radix != -1) {
+                return String.valueOf(radix);
+            }
+        }
+        return String.valueOf(num - 1);
+    }
+
+    private long getRadix(int len, long num) {
+        long l = 2, r = num - 1;
+        while (l < r) {
+            long mid = l + r >>> 1;
+            if (calc(mid, len) >= num) r = mid;
+            else l = mid + 1;
+        }
+        return calc(r, len) == num ? r : -1;
+    }
+
+    private long calc(long radix, int len) {
+        long p = 1;
+        long sum = 0;
+        for (int i = 0; i < len; ++i) {
+            if (Long.MAX_VALUE - sum < p) {
+                return Long.MAX_VALUE;
+            }
+            sum += p;
+            if (Long.MAX_VALUE / p < radix) {
+                p = Long.MAX_VALUE;
+            } else {
+                p *= radix;
+            }
+        }
+        return sum;
+    }
+}