添加algorithm 1 2 3

chenweijie · chenweijie · commit 9110462ecdaf · 2019-09-03T01:13:23.000+08:00
diff --git a/src/main/java/com/chen/algorithm/study/test1/Solution.java b/src/main/java/com/chen/algorithm/study/test1/Solution.java
@@ -0,0 +1,38 @@
+package com.chen.algorithm.study.test1;
+
+import org.junit.Test;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-09-02 23:52
+ */
+public class Solution {
+
+    public int[] twoSum(int[] nums, int target) {
+        for (int i = 0; i < nums.length; i++) {
+            for (int j = i + 1; j < nums.length; j++) {
+                if (nums[i] + nums[j] == target) {
+                    return new int[]{i, j};
+                }
+            }
+        }
+        throw new RuntimeException("没有适合的结果");
+    }
+
+
+    @Test
+    public void testCase() {
+
+        int[] array = {4, 5, 6, 7, 2};
+
+        int[] result = twoSum(array, 9);
+
+        for (int value : result) {
+            System.out.println(value);
+
+        }
+
+    }
+
+
+}
diff --git a/src/main/java/com/chen/algorithm/study/test2/ListNode.java b/src/main/java/com/chen/algorithm/study/test2/ListNode.java
@@ -0,0 +1,18 @@
+package com.chen.algorithm.study.test2;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-09-02 23:06
+ */
+public class ListNode {
+
+    int val;
+
+    ListNode next;
+
+    ListNode(int val) {
+        this.val = val;
+    }
+
+
+}
diff --git a/src/main/java/com/chen/algorithm/study/test2/Solution.java b/src/main/java/com/chen/algorithm/study/test2/Solution.java
@@ -0,0 +1,74 @@
+package com.chen.algorithm.study.test2;
+
+import org.junit.Test;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-09-02 23:05
+ */
+public class Solution {
+
+
+    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+        ListNode result = new ListNode(0);
+        ListNode l3 = result;
+        int nextNum = 0;
+        while (l1 != null || l2 != null) {
+            int x = l1 != null ? l1.val : 0;
+            int y = l2 != null ? l2.val : 0;
+
+            int num = x + y + nextNum;
+            nextNum = 0;
+            if (num > 9) {
+                num = num % 10;
+                nextNum = 1;
+            }
+            if (l1 != null) {
+                l1 = l1.next;
+            }
+
+            if (l2 != null) {
+                l2 = l2.next;
+            }
+
+            l3.next = new ListNode(num);
+            l3 = l3.next;
+        }
+
+        if (nextNum > 0) {
+            l3.next = new ListNode(nextNum);
+        }
+        return result.next;
+    }
+
+
+    @Test
+    public void testCase() {
+
+        ListNode l1_1 = new ListNode(2);
+        ListNode l1_2 = new ListNode(4);
+        ListNode l1_3 = new ListNode(3);
+
+        l1_1.next = l1_2;
+        l1_2.next = l1_3;
+
+
+        ListNode l2_1 = new ListNode(5);
+        ListNode l2_2 = new ListNode(6);
+        ListNode l2_3 = new ListNode(4);
+
+        l2_1.next = l2_2;
+        l2_2.next = l2_3;
+
+
+        ListNode result = addTwoNumbers(l1_1, l2_1);
+
+        System.out.println(result.val);
+        System.out.println(result.next.val);
+        System.out.println(result.next.next.val);
+
+
+    }
+
+
+}
diff --git a/src/main/java/com/chen/algorithm/study/test3/Solution.java b/src/main/java/com/chen/algorithm/study/test3/Solution.java
@@ -0,0 +1,52 @@
+package com.chen.algorithm.study.test3;
+
+import org.junit.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-09-03 00:00
+ */
+public class Solution {
+
+    public int lengthOfLongestSubstring(String s) {
+
+        if (s == null || "".equals(s)) {
+            return 0;
+        }
+
+        if (" ".equals(s)) {
+            return 1;
+        }
+
+        int max = 0;
+        char[] chars = s.toCharArray();
+        Set<Character> set = new HashSet<>();
+        int start = 0;
+        for (int i = 0; i < chars.length; i++) {
+            int count = 0;
+            for (int j = start; j < chars.length; j++) {
+                if (!set.add(chars[j])) {
+                    max = Math.max(max, set.size());
+                    set.clear();
+                    start++;
+                    break;
+                } else {
+                    count++;
+                }
+            }
+            max = Math.max(max, count);
+        }
+        return max;
+    }
+
+
+    @Test
+    public void testCase() {
+        System.out.println(lengthOfLongestSubstring("cdfg"));
+    }
+
+
+}
diff --git a/src/main/java/com/chen/algorithm/study/test3/Solution2.java b/src/main/java/com/chen/algorithm/study/test3/Solution2.java
@@ -0,0 +1,32 @@
+package com.chen.algorithm.study.test3;
+
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-09-03 00:33
+ */
+public class Solution2 {
+
+    public int lengthOfLongestSubstring(String s) {
+        int n = s.length();
+        int max = 0;
+        Map<Character, Integer> characterIntegerMap = new HashMap<>();
+        for (int i = 0, j = 0; j < n; j++) {
+            if (characterIntegerMap.containsKey(s.charAt(j))) {
+                i = Math.max(i, characterIntegerMap.get(s.charAt(j)));
+            }
+            max = Math.max(max, j - i + 1);
+            characterIntegerMap.put(s.charAt(j), j + 1);
+        }
+        return max;
+    }
+
+    @Test
+    public void testCase() {
+        System.out.println(lengthOfLongestSubstring("cdfkfg"));
+    }
+}
