add 1171

Author: fishercoder1534

README.md

@@ -257,6 +257,7 @@ _If you like this project, please leave me a star._ ★
 |1180|[Count Substrings with Only One Distinct Letter](https://leetcode.com/problems/count-substrings-with-only-one-distinct-letter/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1180.java) | |Easy|Math, String|
 |1176|[Diet Plan Performance](https://leetcode.com/problems/diet-plan-performance/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1176.java) | |Easy|Array, Sliding Window|
 |1175|[Prime Arrangements](https://leetcode.com/problems/prime-arrangements/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1175.java) | |Easy|Math|
+|1171|[Remove Zero Sum Consecutive Nodes from Linked List](https://leetcode.com/problems/remove-zero-sum-consecutive-nodes-from-linked-list/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1171.java) | |Medium|LinkedList|
 |1165|[Single-Row Keyboard](https://leetcode.com/problems/single-row-keyboard/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1165.java) | |Easy||
 |1161|[Maximum Level Sum of a Binary Tree](https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1161.java) | |Medium|Graph|
 |1160|[Find Words That Can Be Formed by Characters](https://leetcode.com/problems/find-words-that-can-be-formed-by-characters/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1160.java)| |Easy||

src/main/java/com/fishercoder/solutions/_1171.java

@@ -0,0 +1,75 @@
+package com.fishercoder.solutions;
+
+import com.fishercoder.common.classes.ListNode;
+
+import java.util.*;
+
+public class _1171 {
+    public static class Solution1 {
+        /**
+         * I keep shrinking the array whenever I found there's a range of sum that equals to zero
+         * until the size of the list doesn't change any more.
+         * This is probably not super efficient, but accepted on LeetCode.
+         */
+        public ListNode removeZeroSumSublists(ListNode head) {
+            List<Integer> list = convertToList(head);
+            int size;
+            do {
+                size = list.size();
+                list = shrinkList(list);
+            } while (list.size() != size);
+            return recoverLinkedList(list);
+        }
+
+        private ListNode recoverLinkedList(List<Integer> list) {
+            ListNode pre = new ListNode(-1);
+            ListNode tmp = pre;
+            for (int i = 0; i < list.size(); i++) {
+                tmp.next = new ListNode(list.get(i));
+                tmp = tmp.next;
+            }
+            return pre.next;
+        }
+
+        private List<Integer> convertToList(ListNode head) {
+            List<Integer> list = new ArrayList<>();
+            while (head != null) {
+                if (head.val != 0) {
+                    //if it's zero, we'll just ignore it, this can help us take care of the zero values
+                    list.add(head.val);
+                }
+                head = head.next;
+            }
+            return list;
+        }
+
+        private List<Integer> shrinkList(List<Integer> list) {
+            for (int i = 0; i < list.size(); i++) {
+                int start = i;
+                List<Integer> preSumList = new ArrayList<>();
+                for (int k = 0; k < start; k++) {
+                    preSumList.add(0);
+                }
+                preSumList.add(list.get(i));
+                for (int k = i; k < list.size(); k++) {
+                    if (k > start) {
+                        Integer sum = preSumList.get(k - 1) + list.get(k);
+                        if (sum == 0) {
+                            List<Integer> shrinkedList = new ArrayList<>();
+                            for (int j = 0; j < start; j++) {
+                                shrinkedList.add(list.get(j));
+                            }
+                            for (int j = k + 1; j < list.size(); j++) {
+                                shrinkedList.add(list.get(j));
+                            }
+                            return shrinkedList;
+                        } else {
+                            preSumList.add(sum);
+                        }
+                    }
+                }
+            }
+            return list;
+        }
+    }
+}

src/test/java/com/fishercoder/_1171Test.java

@@ -0,0 +1,52 @@
+package com.fishercoder;
+
+import com.fishercoder.common.utils.LinkedListUtils;
+import com.fishercoder.solutions._1171;
+import com.fishercoder.solutions._96;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1171Test {
+    private static _1171.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1171.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{3, 1}), solution1.removeZeroSumSublists(LinkedListUtils.contructLinkedList(new int[]{1, 2, -3, 3, 1})));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{1, 2, 4}), solution1.removeZeroSumSublists(LinkedListUtils.contructLinkedList(new int[]{1, 2, 3, -3, 4})));
+    }
+
+    @Test
+    public void test3() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{1}), solution1.removeZeroSumSublists(LinkedListUtils.contructLinkedList(new int[]{1, 2, 3, -3, -2})));
+    }
+
+    @Test
+    public void test4() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{5, -2, -5}),
+                solution1.removeZeroSumSublists(LinkedListUtils.contructLinkedList(new int[]{5, -3, -4, 1, 6, -2, -5})));
+    }
+
+    @Test
+    public void test5() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{}),
+                solution1.removeZeroSumSublists(LinkedListUtils.contructLinkedList(new int[]{0})));
+    }
+
+    @Test
+    public void test6() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{2}),
+                solution1.removeZeroSumSublists(LinkedListUtils.contructLinkedList(new int[]{2, 0})));
+    }
+
+}