Add solution for 1011 (#59)

Author: havanagrawal

README.md

@@ -33,6 +33,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |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|
 |1018|[Binary Prefix Divisible By 5](https://leetcode.com/problems/binary-prefix-divisible-by-5/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1018.java) | O(n) | O(1) | |Easy|
 |1014|[Best Sightseeing Pair](https://leetcode.com/problems/best-sightseeing-pair/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1014.java) | O(n) | O(1) | |Medium|
+|1011|[Capacity To Ship Packages Within D Days](https://leetcode.com/problems/capacity-to-ship-packages-within-d-days/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1011.java) | O(nlogn) | O(1) | |Medium|Binary Search|
 |1010|[Pairs of Songs With Total Durations Divisible by 60](https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1010.java) | O(n) | O(1) | |Easy|
 |1009|[Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1009.java) | O(n) | O(1) | |Easy|
 |1003|[Check If Word Is Valid After Substitutions](https://leetcode.com/problems/check-if-word-is-valid-after-substitutions/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1003.java) | O(n) | O(n) | |Medium|

src/main/java/com/fishercoder/solutions/_1011.java

@@ -0,0 +1,73 @@
+package com.fishercoder.solutions;
+
+/**
+ * 1011. Capacity To Ship Packages Within D Days
+ *
+ * A conveyor belt has packages that must be shipped from one port to another within D days.
+ *
+ * The i-th package on the conveyor belt has a weight of weights[i].
+ * Each day, we load the ship with packages on the conveyor belt (in the order given by weights).
+ * We may not load more weight than the maximum weight capacity of the ship.
+ *
+ * Return the least weight capacity of the ship that will result in all the packages on the conveyor belt being shipped within D days.
+ *
+ * Note:
+ *  * 1 <= D <= weights.length <= 50000
+ *  * 1 <= weights[i] <= 500
+ */
+
+public class _1011 {
+    public static class Solution1 {
+        public int daysToShip(int[] weights, int capacity) {
+            int days = 0;
+            int currentShip = 0;
+
+            for (int k : weights) {
+                if (currentShip + k > capacity) {
+                    currentShip = 0;
+                    days += 1;
+                }
+                currentShip += k;
+            }
+
+            return days + 1;
+        }
+
+        public int shipWithinDays(int[] weights, int D) {
+
+            int sum = 0;
+            int max = 0;
+
+            for (int k : weights) {
+                sum += k;
+                max = Math.max(max, k);
+            }
+
+            // Minimum possible capacity needs to be as much as the heaviest package
+            int lower = max;
+            // Maximum possible capacity is the total weight of all packages
+            int upper = sum;
+
+            if (daysToShip(weights, lower) <= D) {
+                return lower;
+            }
+
+            // Guess is for capacity
+            int currentGuess;
+            int bestGuess = -1;
+
+            // Binary search
+            while (lower <= upper) {
+                currentGuess = (upper + lower)/2;
+                if (daysToShip(weights, currentGuess) <= D) {
+                    bestGuess = currentGuess;
+                    upper = currentGuess - 1;
+                } else {
+                    lower = currentGuess + 1;
+                }
+            }
+
+            return bestGuess;
+        }
+    }
+}

src/test/java/com/fishercoder/_1011Test.java

@@ -0,0 +1,34 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1011;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1011Test {
+    private static _1011.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1011.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        int[] weights = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        assertEquals(solution1.shipWithinDays(weights, 5), 15);
+    }
+
+    @Test
+    public void test2() {
+        int[] weights = {3, 2, 2, 4, 1, 4};
+        assertEquals(solution1.shipWithinDays(weights, 3), 6);
+    }
+
+    @Test
+    public void test3() {
+        int[] weights = {1, 2, 3, 1, 1};
+        assertEquals(solution1.shipWithinDays(weights, 4), 3);
+    }
+}