add

5.leetcode/src/com/fanxb/common/Q1.java

@@ -25,6 +25,16 @@ public class Q1 {
         return null;
     }
 
+    public int[] twoSum1(int[] nums, int target) {
+        Map<Integer, Integer> map = new HashMap<>();
+        for (int i = 0; i < nums.length; i++) map.put(nums[i], i);
+        for (int i = 0; i < nums.length; i++) {
+            Integer targetI = map.get(target - nums[i]);
+            if (targetI != null && targetI != i) return new int[]{i, map.get(target - nums[i])};
+        }
+        return null;
+    }
+
     /**
      * 更优，一次循环即可
      *

5.leetcode/src/com/fanxb/common/Q128.java

@@ -0,0 +1,26 @@
+package com.fanxb.common;
+
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class Q128 {
+
+    public int longestConsecutive(int[] nums) {
+        Set<Integer> set = new HashSet<>(nums.length);
+        for (int num : nums) set.add(num);
+        int res = 0;
+        for (int num : nums) {
+            if (!set.contains(num - 1)) {
+                //说明num是一个序列的起点
+                int temp = num, curRes = 1;
+                while (set.contains(++temp)) curRes++;
+                res = Math.max(res, curRes);
+            }
+        }
+        return res;
+    }
+
+    public static void main(String[] args) {
+    }
+}

5.leetcode/src/com/fanxb/common/Q14.java

@@ -35,7 +35,7 @@ public class Q14 {
                 if (res.charAt(j) == strs[i].charAt(j)) temp.append(res.charAt(j));
                 else break;
             }
-            if (temp.isEmpty()) return "";
+            if (temp.length() == 0) return "";
             res = temp.toString();
         }
         return res;

5.leetcode/src/com/fanxb/common/Q202.java

@@ -0,0 +1,25 @@
+package com.fanxb.common;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class Q202 {
+
+    public boolean isHappy(int n) {
+        Set<Long> cache = new HashSet<>();
+        long temp = n;
+        while (true) {
+            String[] strs = Long.toString(temp).split("");
+            long res = 0;
+            for (String s : strs) res += (long) Integer.parseInt(s) * Integer.parseInt(s);
+            if (res == 1) return true;
+            if (cache.contains(res)) return false;
+            cache.add(res);
+            temp = res;
+        }
+    }
+
+    public static void main(String[] args) {
+        new Q202().isHappy(2);
+    }
+}

5.leetcode/src/com/fanxb/common/Q219.java

@@ -0,0 +1,20 @@
+package com.fanxb.common;
+
+import java.util.*;
+
+public class Q219 {
+    public boolean containsNearbyDuplicate(int[] nums, int k) {
+        Map<Integer, Integer> map = new HashMap<>();
+        for (int i = 0; i < nums.length; i++) {
+            int num = nums[i];
+            Integer index = map.get(num);
+            if (index != null && Math.abs(i - index) <= k) return true;
+            map.put(num, i);
+        }
+        return false;
+    }
+
+    public static void main(String[] args) {
+    }
+
+}

5.leetcode/src/com/fanxb/common/Q228.java

@@ -0,0 +1,20 @@
+package com.fanxb.common;
+
+import java.util.LinkedList;
+import java.util.List;
+
+public class Q228 {
+    public List<String> summaryRanges(int[] nums) {
+        List<String> res = new LinkedList<>();
+        if (nums.length == 0) return res;
+        int startIndex = 0, length = nums.length;
+        for (int i = 1; i < length; i++) {
+            if (nums[i] - nums[startIndex] != i - startIndex) {
+                res.add(startIndex == i - 1 ? String.valueOf(nums[startIndex]) : (nums[startIndex] + "->" + nums[i - 1]));
+                startIndex = i;
+            }
+        }
+        res.add(startIndex == length - 1 ? String.valueOf(nums[startIndex]) : (nums[startIndex] + "->" + nums[length - 1]));
+        return res;
+    }
+}

5.leetcode/src/com/fanxb/common/Q242.java

@@ -0,0 +1,24 @@
+package com.fanxb.common;
+
+/**
+ * @author fanxb
+ * @date 2021-10-25-下午4:25
+ */
+public class Q242 {
+    public boolean isAnagram(String s, String t) {
+        int sn = s.length(), tn = t.length();
+        if (sn != tn) return false;
+        int[] count = new int[128];
+        for (int i = 0; i < sn; i++) {
+            count[s.charAt(i)]++;
+            count[t.charAt(i)]--;
+        }
+        for (int j : count) if (j != 0) return false;
+        return true;
+    }
+
+
+    public static void main(String[] args) {
+        int[][] params = {{-1, 3}};
+    }
+}

5.leetcode/src/com/fanxb/common/Q49.java

@@ -0,0 +1,25 @@
+package com.fanxb.common;
+
+import java.util.*;
+
+/**
+ * Created with IntelliJ IDEA
+ *
+ * @author fanxb
+ * Date: 2020/6/9 15:10
+ */
+public class Q49 {
+
+    public List<List<String>> groupAnagrams(String[] strs) {
+        Map<String, List<String>> map = new HashMap<>();
+        for (String str : strs) {
+            char[] chars = str.toCharArray();
+            Arrays.sort(chars);
+            map.computeIfAbsent(new String(chars), k -> new LinkedList<>()).add(str);
+        }
+        return new ArrayList<>(map.values());
+    }
+
+    public static void main(String[] args) {
+    }
+}