Format

Author: mengli

AddBinary.java

@@ -1,44 +1,41 @@
-
-
 /**
  * Given two binary strings, return their sum (also a binary string).
- * 
- * For example, a = "11" b = "1" Return "100".
+ *
+ * <p>For example, a = "11" b = "1" Return "100".
  */
-
 public class AddBinary {
-	public String addBinary(String a, String b) {
-		int i = a.length() - 1;
-		int j = b.length() - 1;
-		int da = 0;
-		int db = 0;
-		int adv = 0;
-		StringBuffer result = new StringBuffer();
-		while (i >= 0 && j >= 0) {
-			da = a.charAt(i--) == '0' ? 0 : 1;
-			db = b.charAt(j--) == '0' ? 0 : 1;
-			int d = da + db + adv;
-			result.append(d % 2 == 0 ? '0' : '1');
-			adv = d >> 1;
-		}
-		if (i >= 0) {
-			while (i >= 0) {
-				da = a.charAt(i--) == '0' ? 0 : 1;
-				int d = da + adv;
-				result.append(d % 2 == 0 ? '0' : '1');
-				adv = d >> 1;
-			}
-		} else if (j >= 0) {
-			while (j >= 0) {
-				db = b.charAt(j--) == '0' ? 0 : 1;
-				int d = db + adv;
-				result.append(d % 2 == 0 ? '0' : '1');
-				adv = d >> 1;
-			}
-		}
-		if (adv == 1) {
-			result.append('1');
-		}
-		return result.reverse().toString();
-	}
-}
+  public String addBinary(String a, String b) {
+    int i = a.length() - 1;
+    int j = b.length() - 1;
+    int da = 0;
+    int db = 0;
+    int adv = 0;
+    StringBuffer result = new StringBuffer();
+    while (i >= 0 && j >= 0) {
+      da = a.charAt(i--) == '0' ? 0 : 1;
+      db = b.charAt(j--) == '0' ? 0 : 1;
+      int d = da + db + adv;
+      result.append(d % 2 == 0 ? '0' : '1');
+      adv = d >> 1;
+    }
+    if (i >= 0) {
+      while (i >= 0) {
+        da = a.charAt(i--) == '0' ? 0 : 1;
+        int d = da + adv;
+        result.append(d % 2 == 0 ? '0' : '1');
+        adv = d >> 1;
+      }
+    } else if (j >= 0) {
+      while (j >= 0) {
+        db = b.charAt(j--) == '0' ? 0 : 1;
+        int d = db + adv;
+        result.append(d % 2 == 0 ? '0' : '1');
+        adv = d >> 1;
+      }
+    }
+    if (adv == 1) {
+      result.append('1');
+    }
+    return result.reverse().toString();
+  }
+}

AddTwoNumbers.java

@@ -1,49 +1,44 @@
-
-
 /**
- * You are given two linked lists representing two non-negative numbers. 
- * 
- * The digits are stored in reverse order and each of their nodes contain a single digit.
- * 
- * Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
- * 
- * Output: 7 -> 0 -> 8
+ * You are given two linked lists representing two non-negative numbers.
+ *
+ * <p>The digits are stored in reverse order and each of their nodes contain a single digit.
+ *
+ * <p>Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
+ *
+ * <p>Output: 7 -> 0 -> 8
  */
-
 public class AddTwoNumbers {
-	public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
-		if (l1 == null)
-			return l2;
-		if (l2 == null)
-			return l1;
-		ListNode head = new ListNode(0);
-		ListNode cur = head;
-		int plus = 0;
-		while (l1 != null && l2 != null) {
-			int sum = l1.val + l2.val + plus;
-			plus = sum / 10;
-			sum = sum % 10;
-			cur.next = new ListNode(sum);
-			cur = cur.next;
-			l1 = l1.next;
-			l2 = l2.next;
-		}
-		if (l1 != null) {
-			if (plus != 0) {
-				cur.next = addTwoNumbers(l1, new ListNode(plus));
-			} else {
-				cur.next = l1;
-			}
-		} else if (l2 != null) {
-			if (plus != 0) {
-				cur.next = addTwoNumbers(l2, new ListNode(plus));
-			} else {
-				cur.next = l2;
-			}
-		} else if (plus != 0) {
-			cur.next = new ListNode(plus);
-		}
+  public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+    if (l1 == null) return l2;
+    if (l2 == null) return l1;
+    ListNode head = new ListNode(0);
+    ListNode cur = head;
+    int plus = 0;
+    while (l1 != null && l2 != null) {
+      int sum = l1.val + l2.val + plus;
+      plus = sum / 10;
+      sum = sum % 10;
+      cur.next = new ListNode(sum);
+      cur = cur.next;
+      l1 = l1.next;
+      l2 = l2.next;
+    }
+    if (l1 != null) {
+      if (plus != 0) {
+        cur.next = addTwoNumbers(l1, new ListNode(plus));
+      } else {
+        cur.next = l1;
+      }
+    } else if (l2 != null) {
+      if (plus != 0) {
+        cur.next = addTwoNumbers(l2, new ListNode(plus));
+      } else {
+        cur.next = l2;
+      }
+    } else if (plus != 0) {
+      cur.next = new ListNode(plus);
+    }
 
-		return head.next;
-	}
-}
+    return head.next;
+  }
+}

Anagrams.java

@@ -1,44 +1,40 @@
-
-
 import java.util.ArrayList;
 import java.util.Arrays;
 
 /**
  * Given an array of strings, return all groups of strings that are anagrams.
- * 
- * Note: All inputs will be in lower-case.
+ *
+ * <p>Note: All inputs will be in lower-case.
  */
-
 public class Anagrams {
-	public ArrayList<String> anagrams(String[] strs) {
-		ArrayList<String> ret = new ArrayList<String>();
-		ArrayList<String> ar = new ArrayList<String>();
-		for (String s : strs) {
-			char[] c = s.toCharArray();
-			Arrays.sort(c);
-			ar.add(new String(c));
-		}
-		int[] list = new int[strs.length];
-		int tmp = 0;
-		for (int i = 0; i < ar.size(); i++) {
-			if (list[i] == 0) {
-				list[i] = 1;
-				tmp = 1;
-				for (int j = i + 1; j < ar.size(); j++) {
-					if (list[j] == 0 && ar.get(i).equals(ar.get(j))) {
-						list[j] = 1;
-						tmp++;
-					}
-				}
-				if (tmp == 1) {
-					list[i] = 0;
-				}
-			}
-		}
-		for (int i = 0; i < list.length; i++) {
-			if (list[i] == 1)
-				ret.add(strs[i]);
-		}
-		return ret;
-	}
-}
+  public ArrayList<String> anagrams(String[] strs) {
+    ArrayList<String> ret = new ArrayList<String>();
+    ArrayList<String> ar = new ArrayList<String>();
+    for (String s : strs) {
+      char[] c = s.toCharArray();
+      Arrays.sort(c);
+      ar.add(new String(c));
+    }
+    int[] list = new int[strs.length];
+    int tmp = 0;
+    for (int i = 0; i < ar.size(); i++) {
+      if (list[i] == 0) {
+        list[i] = 1;
+        tmp = 1;
+        for (int j = i + 1; j < ar.size(); j++) {
+          if (list[j] == 0 && ar.get(i).equals(ar.get(j))) {
+            list[j] = 1;
+            tmp++;
+          }
+        }
+        if (tmp == 1) {
+          list[i] = 0;
+        }
+      }
+    }
+    for (int i = 0; i < list.length; i++) {
+      if (list[i] == 1) ret.add(strs[i]);
+    }
+    return ret;
+  }
+}

BalancedBinaryTree.java

@@ -1,28 +1,22 @@
-
 /**
  * Given a binary tree, determine if it is height-balanced.
- * 
- * For this problem, a height-balanced binary tree is defined as a binary tree
- * in which the depth of the two subtrees of every node never differ by more
- * than 1.
- * 
+ *
+ * <p>For this problem, a height-balanced binary tree is defined as a binary tree in which the depth
+ * of the two subtrees of every node never differ by more than 1.
  */
-
 public class BalancedBinaryTree {
-	public boolean isBalanced(TreeNode root) {
-		return determine(root) >= 0 ? true : false;
-	}
+  public boolean isBalanced(TreeNode root) {
+    return determine(root) >= 0 ? true : false;
+  }
 
-	private int determine(TreeNode root) {
-		if (root == null) {
-			return 0;
-		} else {
-			int leftDepth = determine(root.left);
-			int rightDepth = determine(root.right);
-			if (leftDepth < 0 || rightDepth < 0
-					|| Math.abs(leftDepth - rightDepth) > 1)
-				return -1;
-			return Math.max(leftDepth, rightDepth) + 1;
-		}
-	}
-}
+  private int determine(TreeNode root) {
+    if (root == null) {
+      return 0;
+    } else {
+      int leftDepth = determine(root.left);
+      int rightDepth = determine(root.right);
+      if (leftDepth < 0 || rightDepth < 0 || Math.abs(leftDepth - rightDepth) > 1) return -1;
+      return Math.max(leftDepth, rightDepth) + 1;
+    }
+  }
+}

BestTimetoBuyandSellStock.java

@@ -1,26 +1,22 @@
-
-
 /**
- * Say you have an array for which the ith element is the price of a given stock
- * on day i.
- * 
- * If you were only permitted to complete at most one transaction (ie, buy one
- * and sell one share of the stock), design an algorithm to find the maximum
- * profit.
+ * Say you have an array for which the ith element is the price of a given stock on day i.
+ *
+ * <p>If you were only permitted to complete at most one transaction (ie, buy one and sell one share
+ * of the stock), design an algorithm to find the maximum profit.
  */
 public class BestTimetoBuyandSellStock {
-	public int maxProfit(int[] prices) {
-		int lowest = 0;
-		int maxProfit = 0;
-		if (prices.length > 0) {
-			lowest = prices[0];
-			for (int i = 0; i < prices.length; i++) {
-				if (lowest > prices[i]) {
-					lowest = prices[i];
-				}
-				maxProfit = Math.max(maxProfit, prices[i] - lowest);
-			}
-		}
-		return maxProfit;
-	}
-}
+  public int maxProfit(int[] prices) {
+    int lowest = 0;
+    int maxProfit = 0;
+    if (prices.length > 0) {
+      lowest = prices[0];
+      for (int i = 0; i < prices.length; i++) {
+        if (lowest > prices[i]) {
+          lowest = prices[i];
+        }
+        maxProfit = Math.max(maxProfit, prices[i] - lowest);
+      }
+    }
+    return maxProfit;
+  }
+}

BestTimetoBuyandSellStockII.java

@@ -1,24 +1,19 @@
-
-
 /**
- * Say you have an array for which the ith element is the price of a given stock
- * on day i.
- * 
- * Design an algorithm to find the maximum profit. You may complete as many
- * transactions as you like (ie, buy one and sell one share of the stock
- * multiple times). However, you may not engage in multiple transactions at the
- * same time (ie, you must sell the stock before you buy again).
+ * Say you have an array for which the ith element is the price of a given stock on day i.
+ *
+ * <p>Design an algorithm to find the maximum profit. You may complete as many transactions as you
+ * like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in
+ * multiple transactions at the same time (ie, you must sell the stock before you buy again).
  */
-
 public class BestTimetoBuyandSellStockII {
-	public int maxProfit(int[] prices) {
-		int profit = 0;
-		for (int i = 1; i < prices.length; i++) {
-			int d = prices[i] - prices[i - 1];
-			if (d > 0) {
-				profit += d;
-			}
-		}
-		return profit;
-	}
-}
+  public int maxProfit(int[] prices) {
+    int profit = 0;
+    for (int i = 1; i < prices.length; i++) {
+      int d = prices[i] - prices[i - 1];
+      if (d > 0) {
+        profit += d;
+      }
+    }
+    return profit;
+  }
+}