Add solution for 1029

Author: havanagrawal

README.md

@@ -28,6 +28,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |  #  |      Title     |   Solutions   | Time          | Space         | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|---------------|---------------|--------|-------------|-------------
 |1030|[Matrix Cells in Distance Order](https://leetcode.com/problems/matrix-cells-in-distance-order/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1030.java) | O(R*C) | O(1) | |Easy|
+|1029|[Two City Scheduling](https://leetcode.com/problems/two-city-scheduling/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1029.java)| O(nlogn) | O(1) | |Easy| Array, Sorting |
 |1022|[Sum of Root To Leaf Binary Numbers](https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1022.java) | O(n) | O(n) | |Easy|
 |1021|[Remove Outermost Parentheses](https://leetcode.com/problems/remove-outermost-parentheses/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1021.java) | O(n) | O(n) | |Easy|
 |1020|[Number of Enclaves](https://leetcode.com/problems/number-of-enclaves/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1020.java) | O(mn) | O(mn) | |Medium|Graph, DFS, BFS, recursion|

src/main/java/com/fishercoder/solutions/_1029.java

@@ -0,0 +1,28 @@
+package com.fishercoder.solutions;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/**
+ * There are 2N people a company is planning to interview.
+ * The cost of flying the i-th person to city A is costs[i][0], and
+ * the cost of flying the i-th person to city B is costs[i][1].
+ *
+ * Return the minimum cost to fly every person to a city such that exactly N people arrive in each city.
+ */
+
+public class _1029 {
+    public static class Solution1 {
+        public int twoCitySchedCost(int[][] costs) {
+            Arrays.sort(costs, Comparator.comparing((int[] arr) -> arr[0] - arr[1]));
+            int totalCost = 0;
+            final int n = costs.length;
+
+            for (int i = 0; i < n; ++i) {
+                // 2i/n = I(i >= n/2), i.e. 1 if true, 0 if false
+                totalCost += costs[i][2*i/n];
+            }
+            return totalCost;
+        }
+    }
+}

src/test/java/com/fishercoder/_1029Test.java

@@ -0,0 +1,30 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1029;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1029Test {
+    private static _1029.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1029.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        /*
+         * The first person goes to city A for a cost of 10.
+         * The second person goes to city A for a cost of 30.
+         * The third person goes to city B for a cost of 50.
+         * The fourth person goes to city B for a cost of 20.
+
+         * The total minimum cost is 10 + 30 + 50 + 20 = 110 to have half the people interviewing in each city.
+         */
+        int[][] costs = {{10, 20}, {30, 200}, {400, 50}, {30, 20}};
+        assertEquals(solution1.twoCitySchedCost(costs), 110);
+    }
+}