solution

chenweijie · chenweijie · commit fbe3027f98ba · 2020-04-06T00:01:28.000+08:00
diff --git a/src/main/java/com/chen/algorithm/study/test240/Solution.java b/src/main/java/com/chen/algorithm/study/test240/Solution.java
@@ -0,0 +1,54 @@
+package com.chen.algorithm.study.test240;
+
+/**
+ * https://leetcode-cn.com/problems/search-a-2d-matrix-ii/solution/er-fen-fa-pai-chu-fa-python-dai-ma-java-dai-ma-by-/
+ *
+ * @author :  chen weijie
+ * @Date: 2019-12-22 14:26
+ */
+public class Solution {
+
+
+    /**
+     * 从左下角开始
+     * <p>
+     * 如果当前数比目标元素小，当前列就不可能存在目标值，“指针”就向右移一格（纵坐标加 11）；
+     * 如果当前数比目标元素大，当前行就不可能存在目标值，“指针”就向上移一格（横坐标减 11）。
+     *
+     * @param matrix
+     * @param target
+     * @return
+     */
+    public boolean searchMatrix(int[][] matrix, int target) {
+
+        int rows = matrix.length;
+        if (rows == 0) {
+            return false;
+        }
+
+        int col = matrix[0].length;
+
+        if (col == 0) {
+            return false;
+        }
+
+        int x = rows - 1;
+        int y = 0;
+        int value;
+
+        while (x >= 0 && y < col) {
+            value = matrix[x][y];
+            if (value > target) {
+                x--;
+            } else if (value < target) {
+                y++;
+            } else {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+
+}
diff --git a/src/main/java/com/chen/algorithm/study/test279/Solution.java b/src/main/java/com/chen/algorithm/study/test279/Solution.java
@@ -0,0 +1,37 @@
+package com.chen.algorithm.study.test279;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-12-22 15:13
+ */
+public class Solution {
+
+
+    int[] memo;
+
+    public int numSquares(int n) {
+        memo = new int[n + 1];
+
+        return numSqu(n);
+
+    }
+
+
+    public int numSqu(int n) {
+        if (memo[n] != 0) {
+            return memo[n];
+        }
+
+        int val = (int) Math.sqrt(n);
+        if (val * val == n) {
+            return memo[0] = 1;
+        }
+        int res = Integer.MAX_VALUE;
+        for (int i = 1; i * i < n; i++) {
+            res = Math.min(res, numSqu(n - i * i) + 1);
+        }
+
+        return memo[n] = res;
+    }
+
+}
diff --git a/src/main/java/com/chen/algorithm/study/test287/Solution.java b/src/main/java/com/chen/algorithm/study/test287/Solution.java
@@ -0,0 +1,25 @@
+package com.chen.algorithm.study.test287;
+
+import java.util.Arrays;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-12-22 16:22
+ */
+public class Solution {
+
+
+    public int findDuplicate(int[] nums) {
+
+        Arrays.sort(nums);
+
+        for (int i = 1; i < nums.length; i++) {
+            if (nums[i] == nums[i - 1]) {
+                return nums[i];
+            }
+        }
+        return -1;
+    }
+
+
+}
diff --git a/src/main/java/com/chen/algorithm/study/test300/Solution.java b/src/main/java/com/chen/algorithm/study/test300/Solution.java
@@ -0,0 +1,34 @@
+package com.chen.algorithm.study.test300;
+
+/**
+ * @author :  chen weijie
+ * @Date: 2019-12-22 16:28
+ */
+public class Solution {
+
+    public int lengthOfLIST(int[] nums) {
+
+        if (nums.length == 0) {
+            return 0;
+        }
+
+
+        int max = 1;
+        int length = 1;
+        int temp = nums[0];
+        for (int i = 1; i < nums.length; i++) {
+            if (nums[i] > temp) {
+                length++;
+                max = Math.max(length, max);
+                temp = nums[i];
+            } else {
+                temp = nums[i - 1];
+                length = 1;
+            }
+        }
+
+
+        return max;
+    }
+
+}
