solve 268.missing-number

Author: andavid

vscode/268.missing-number.java

@@ -0,0 +1,45 @@
+/*
+ * @lc app=leetcode id=268 lang=java
+ *
+ * [268] Missing Number
+ *
+ * https://leetcode.com/problems/missing-number/description/
+ *
+ * algorithms
+ * Easy (47.56%)
+ * Total Accepted:    263.6K
+ * Total Submissions: 549.2K
+ * Testcase Example:  '[3,0,1]'
+ *
+ * Given an array containing n distinct numbers taken from 0, 1, 2, ..., n,
+ * find the one that is missing from the array.
+ *
+ * Example 1:
+ *
+ *
+ * Input: [3,0,1]
+ * Output: 2
+ *
+ *
+ * Example 2:
+ *
+ *
+ * Input: [9,6,4,2,3,5,7,0,1]
+ * Output: 8
+ *
+ *
+ * Note:
+ * Your algorithm should run in linear runtime complexity. Could you implement
+ * it using only constant extra space complexity?
+ */
+class Solution {
+  public int missingNumber(int[] nums) {
+    int n = nums.length;
+    int result = n;
+    for (int i = 0; i < n; i++) {
+      result = result ^ i ^ nums[i];
+    }
+    return result;
+  }
+}
+