150523

Author: aluferraz

src/Main.java

@@ -3,6 +3,7 @@
 import leetcode.editor.en.Q1259.HandshakesThatDontCross;
 import leetcode.editor.en.Q1498.NumberOfSubsequencesThatSatisfyTheGivenSumCondition;
 import leetcode.editor.en.Q1697.CheckingExistenceOfEdgeLengthLimitedPaths;
+import leetcode.editor.en.Q1721.SwappingNodesInALinkedList;
 import leetcode.editor.en.Q1752.CheckIfArrayIsSortedAndRotated;
 import leetcode.editor.en.Q1799.MaximizeScoreAfterNOperations;
 import leetcode.editor.en.Q188.BestTimeToBuyAndSellStockIv;
@@ -15,6 +16,7 @@
 import leetcode.editor.en.Q474.OnesAndZeroes;
 import leetcode.editor.en.Q518.CoinChangeII;
 import leetcode.editor.en.Q54.SpiralMatrix;
+import leetcode.editor.en.Q639.DecodeWaysIi;
 import leetcode.editor.en.Q649.Dota2Senate;
 import leetcode.editor.en.Q651.FourKeysKeyboard;
 import leetcode.editor.en.Q91.DecodeWays;
@@ -32,7 +34,7 @@
 public class Main {
     public static void main(String[] args) throws IOException {
 
-        System.out.println(new MaximizeScoreAfterNOperations().maxScore(toIntArray("[370435,481435,953948,282360,691237,574616,638525,764832]\n")));
+        System.out.println(new DecodeWaysIi().numDecodings("********"));
 
     }
 

src/leetcode/editor/en/Q1721/SwappingNodesInALinkedList.java

@@ -0,0 +1,72 @@
+package leetcode.editor.en.Q1721;
+
+import java.util.*;
+
+import javafx.util.Pair;
+
+class ListNode {
+    int val;
+    ListNode next;
+
+    ListNode() {
+    }
+
+    ListNode(int val) {
+        this.val = val;
+    }
+
+    ListNode(int val, ListNode next) {
+        this.val = val;
+        this.next = next;
+    }
+}
+//leetcode submit region begin(Prohibit modification and deletion)
+
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ * int val;
+ * ListNode next;
+ * ListNode() {}
+ * ListNode(int val) { this.val = val; }
+ * ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+    public ListNode swapNodes(ListNode head, int k) {
+        if (head == null) return null;
+        int length = 0;
+        ListNode current = head;
+        ListNode beginning = head;
+        ListNode end = head;
+        while (current != null) {
+            length++;
+            current = current.next;
+        }
+        k %= length;
+        for (int i = 0; i < k - 1; i++) {
+            if (beginning.next == null) break;
+            beginning = beginning.next;
+        }
+        for (int i = 0; i < length - k; i++) {
+            if (end.next == null) break;
+            end = end.next;
+        }
+
+        int temp = beginning.val;
+        beginning.val = end.val;
+        end.val = temp;
+        return head;
+
+
+    }
+}
+//leetcode submit region end(Prohibit modification and deletion)
+
+
+public class SwappingNodesInALinkedList extends Solution {
+
+    public ListNode swapNodes() {
+        return super.swapNodes(new ListNode(1, new ListNode(2, new ListNode(3, new ListNode(4, new ListNode(5))))), 2);
+    }
+}

src/leetcode/editor/en/Q639/DecodeWaysIi.java

@@ -0,0 +1,94 @@
+package leetcode.editor.en.Q639;
+
+import java.util.*;
+
+import javafx.util.Pair;
+
+//leetcode submit region begin(Prohibit modification and deletion)
+class Solution {
+
+    Integer[][] cache;
+
+    private int MOD = 1000000007;
+
+    public int numDecodings(String s) {
+        if (
+                s.charAt(0) == '0' ||
+                        s.contains("30" ) ||
+                        s.contains("40" ) ||
+                        s.contains("50" ) ||
+                        s.contains("60" ) ||
+                        s.contains("70" ) ||
+                        s.contains("80" ) ||
+                        s.contains("90" ) ||
+                        s.contains("00" )
+        ) return 0;
+        cache = new Integer[s.length()][11];
+
+
+        return (numDecodingsHelper(s.length() - 1, new StringBuilder(s)) % MOD);
+
+
+    }
+
+    private int numDecodingsHelper(int i, StringBuilder s) {
+        if (i < 0) return 1;
+        int ans = 0;
+        char c = s.charAt(i);
+        int cacheKey = c == '*' ? 10 : c - '0';
+
+
+        if (cache[i][cacheKey] != null) {
+            return cache[i][cacheKey];
+        }
+
+        if (c == '*') {
+            for (int j = 1; j <= 9; j++) {
+                s.setCharAt(i, String.valueOf(j).charAt(0));
+                ans = (ans % MOD + (numDecodingsHelper(i, s) % MOD));
+            }
+            s.setCharAt(i, '*');
+            cache[i][cacheKey] = ans;
+            return ans;
+        }
+        int current = Character.getNumericValue(c);
+        if (current == 0) {
+            char prevC = s.charAt(i - 1);
+            if (prevC == '*') {
+                ans = (2 * (numDecodingsHelper(i - 2, s) % MOD) % MOD);
+            } else {
+                ans = (numDecodingsHelper(i - 2, s) % MOD);
+            }
+            cache[i][cacheKey] = ans;
+            return ans;
+        }
+        ans = numDecodingsHelper(i - 1, s) % MOD;
+        if (i > 0) {
+            char prevC = s.charAt(i - 1);
+            if (prevC == '*') {
+                for (int j = 1; j <= 9; j++) {
+                    int prev = j;
+                    int combination = (prev * 10) + current;
+                    if (combination >= 1 && combination <= 26) {
+                        ans = (ans % MOD + (numDecodingsHelper(i - 2, s) % MOD));
+                    }
+                }
+            } else {
+                int prev = Character.getNumericValue(prevC);
+                int combination = (prev * 10) + current;
+                if (combination >= 10 && combination <= 26) {
+                    ans = (ans % MOD + (numDecodingsHelper(i - 2, s) % MOD));
+                }
+            }
+        }
+        cache[i][cacheKey] = ans;
+        return ans;
+
+
+    }
+}
+//leetcode submit region end(Prohibit modification and deletion)
+
+
+public class DecodeWaysIi extends Solution {
+}