Merge branch 'master' of https://github.com/jinshendan/Leetcode

Author: MagicienDeCode

June-LeetCoding-Challenge/03-Two-City-Scheduling/Two-City-Scheduling.cs

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+public class Helper {
+    public int a;
+    public int b;
+    public int diff {get {return b-a;}}
+}
+
+public class Solution {
+    public int TwoCitySchedCost(int[][] costs) {
+        var helpers = new List<Helper>();
+        for(int i = 0; i < costs.Length; i++)
+        {
+            helpers.Add(new Helper(){
+                a = costs[i][0],
+                b = costs[i][1],
+            });
+        }
+        helpers = helpers.OrderBy(h => h.diff ).ToList();
+        
+        int result = 0;
+        for(int i = 0; i < helpers.Count; i++)
+        {
+            var helper = helpers[i];
+            result += i < helpers.Count/2 ? helper.b : helper.a;
+        }
+        return result;
+    }
+}

June-LeetCoding-Challenge/03-Two-City-Scheduling/Two-City-Scheduling.scala

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+class Question03 {
+  // sort by difference O(n2)
+  object Solution {
+    def twoCitySchedCost(costs: Array[Array[Int]]): Int = {
+      costs.sortBy(t => t(0) - t(1)).zipWithIndex.foldLeft(0) {
+        case (acc, (t, index)) => acc + (if (index < costs.length / 2) t(0) else t(1))
+      }
+    }
+  }
+}

June-LeetCoding-Challenge/04-Reverse-String/Reverse-String.cpp

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+class Solution {
+public:
+    void reverseString(vector<char>& s) {
+        int n = s.size();
+        for (int i = 0; i < n / 2; i++){
+            char t = s[i];
+            s[i] = s[n - i - 1];
+            s[n - i- 1] = t;
+        }
+    }
+};

June-LeetCoding-Challenge/04-Reverse-String/Reverse-String.js

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+/**
+ * @param {character[]} s
+ * @return {void} Do not return anything, modify s in-place instead.
+ */
+var reverseString = function(s) {
+    var i = 0;
+    var j = s.length-1;
+    while(i<j){
+        let tmp = s[i];
+        s[i]=s[j];
+        s[j]=tmp;
+        i++;
+        j--;
+    }
+    return s;
+};

June-LeetCoding-Challenge/04-Reverse-String/Reverse-String.scala

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+class Question04 {
+
+  object Solution {
+    def reverseString(s: Array[Char]): Unit = {
+      var index = 0
+      //not necessary to revert middle char in a odd array
+      while (index < (s.length.toDouble - 1) / 2) {
+        val tmp = s(index)
+        s(index) = s(s.length - 1 - index)
+        s(s.length - 1 - index) = tmp
+        index += 1
+      }
+    }
+  }
+
+}