✨ 两数相加

datastructure/src/main/java/org/alis/algorithm/leetcode/LeetCode18.java

@@ -0,0 +1,106 @@
+package org.alis.algorithm.leetcode;
+
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * 给定一个坐标 返回两个数据相加
+ * 数组数据不重复
+ *
+ * @author lc
+ * @date 2023/10/28 14:32
+ */
+public class LeetCode18 {
+
+    private final int[] ints = {3, 2, 1, 4};
+    private final int target = 6;
+
+    public void exec() {
+        // 基础版本
+        for (int i = 0; i < ints.length; i++) {
+            for (int j = 0; j < ints.length; j++) {
+                if (target == ints[j] + ints[i]) {
+                    System.out.println("target 下标 是 " + i + ":" + j);
+                }
+            }
+        }
+    }
+
+    public int[] half(int[] array, int ta) {
+        int courseOne = array.length / 2;
+        // 先获取目标一半的数据
+        int addOne = array[courseOne];
+        while (true) {
+            // 开始走计算
+            if (addOne <= ta) {
+                int i = ta - addOne;
+                int search;
+                if (i > addOne) {
+                    // 向上找
+                    search = search(i, array, courseOne, array.length);
+                } else {
+                    // 向下找
+                    search = search(i, array, 0, courseOne);
+                }
+                if (search > -1 && search != courseOne) {
+                    return new int[]{courseOne, search};
+                }
+            }
+            if (courseOne == 0) {
+                courseOne = array.length - 1;
+            } else {
+                courseOne = courseOne / 2;
+            }
+            addOne = array[courseOne];
+
+        }
+
+    }
+
+
+    private int search(int i, int[] array, int start, int end) {
+        int left = start;
+        int right = end;
+
+        while (left <= right) { // 注意
+            int mid = (right + left) / 2;
+            // 避免边际查询
+            if (mid < 0 || mid >= array.length) {
+                return -1;
+            }
+            if (array[mid] == i)
+                return mid;
+            else if (array[mid] < i)
+                left = mid + 1; // 注意
+            else if (array[mid] > i)
+                right = mid - 1; // 注意
+        }
+        return -1;
+
+    }
+
+    public int[] hash() {
+        Map<Integer, Integer> map = new HashMap<>();
+        // hashMap
+        for (int i = 0; i < ints.length; i++) {
+            int two = target - ints[i];
+            if (map.containsKey(two)) {
+                return new int[]{map.get(two), i};
+            }
+            map.put(ints[i], i);
+        }
+        return new int[]{};
+    }
+
+
+    public static void main(String[] args) {
+        LetCode letCode = new LetCode();
+        letCode.hash();
+    }
+
+
+
+
+
+}