array two

Author: jackzhenguo

Array/Array.Lib/ContainsItemSln.cs

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+/* ==============================================================================
+ * 功能描述：ContainsItemSln  
+ * 创 建 者：gz
+ * 创建日期：2017/5/3 15:59:33
+ * ==============================================================================*/
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Array.Lib
+{
+    /// <summary>
+    /// ContainsItemSln
+    /// </summary>
+    public class ContainsItemSln
+    {
+        //Given an array of integers, find if the array contains any duplicates. Your function should return true
+        //if any value appears at least twice in the array, and it should return false if every element is distinct.
+        public bool ContainsDuplicate(int[] nums)
+        {
+            HashSet<int> set = new HashSet<int>();
+            foreach (var item in nums)
+            {
+                if (set.Contains(item))
+                    return true;
+                set.Add(item);
+            }
+            return false;
+        }
+
+    }
+}

Array/Array.Lib/FindPairsSln.cs

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+/* ==============================================================================
+ * 功能描述：FindPairsSln  
+ * 创 建 者：gz
+ * 创建日期：2017/5/3 16:01:15
+ * ==============================================================================*/
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Array.Lib
+{
+    /// <summary>
+    /// FindPairsSln
+    /// </summary>
+
+    //    Given an array of integers and an integer k, you need to find the number of unique k-diff pairs in the array. 
+    //    Here a k-diff pair is defined as an integer pair (i, j), where i and j are both numbers in the array and their absolute difference is k.
+
+    //Example 1:
+    //Input: [3, 1, 4, 1, 5], k = 2
+    //Output: 2
+    //Explanation: There are two 2-diff pairs in the array, (1, 3) and (3, 5).
+    //Although we have two 1s in the input, we should only return the number of unique pairs.
+    //Example 2:
+    //Input:[1, 2, 3, 4, 5], k = 1
+    //Output: 4
+    //Explanation: There are four 1-diff pairs in the array, (1, 2), (2, 3), (3, 4) and (4, 5).
+    //Example 3:
+    //Input: [1, 3, 1, 5, 4], k = 0
+    //Output: 1
+    //Explanation: There is one 0-diff pair in the array, (1, 1).
+    public class FindPairsSln
+    {
+        public int FindPairs(int[] nums, int k)
+        {
+            int sum = 0;
+            if (nums.Length == 0 || nums.Length == 1) return 0;
+            System.Array.Sort(nums);
+            for (int i = 0; i < nums.Length; i++)
+            {
+                bool eql = false;
+                for (int j = i + 1; j < nums.Length; j++)
+                {
+                    while (j < nums.Length && nums[j] == nums[i])
+                    {
+                        j++;
+                        eql = true;
+                    }
+                    if (eql) //找到了相等元素
+                    {
+                        i = j - 1; //j-1>i=0 //i等于某一块相等元素的末端点
+                        if (k == 0)
+                        {
+                            sum++;
+                            break;
+                        }
+                        eql = false;
+                    }
+                    while (j + 1 < nums.Length && nums[j + 1] == nums[j])
+                        j++; //j等于后一块相等元素的末端点                 
+                    if (j < nums.Length && nums[j] - nums[i] > k) //
+                        break;
+                    if (j < nums.Length && nums[j] - nums[i] == k)
+                        sum++;
+                }
+            }
+            return sum;
+        }
+
+    }
+}