add 880

fishercoder1534 · fishercoder1534 · commit 69ffa7cc57a4 · 2020-02-15T17:51:31.000-08:00
diff --git a/README.md b/README.md
@@ -172,6 +172,7 @@ _If you like this project, please leave me a star._ &#9733;
 |885|[Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_885.java)  |[:tv:](https://www.youtube.com/watch?v=0qep3f9cqVs) |Medium|
 |884|[Uncommon Words from Two Sentences](https://leetcode.com/problems/uncommon-words-from-two-sentences/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_884.java) | |Easy|
 |883|[Projection Area of 3D Shapes](https://leetcode.com/problems/projection-area-of-3d-shapes/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_883.java) | |Easy|Math
+|880|[Decoded String at Index](https://leetcode.com/problems/decoded-string-at-index/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_880.java) | |Medium|Stack
 |876|[Middle of the Linked List](https://leetcode.com/problems/middle-of-the-linked-list/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_876.java) | |Easy|
 |872|[Leaf-Similar Trees](https://leetcode.com/problems/leaf-similar-trees/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_872.java) |  |Easy| DFS, recursion
 |868|[Binary Gap](https://leetcode.com/problems/binary-gap/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_868.java) |  |Easy|
diff --git a/src/main/java/com/fishercoder/solutions/_880.java b/src/main/java/com/fishercoder/solutions/_880.java
@@ -0,0 +1,45 @@
+package com.fishercoder.solutions;
+
+/**
+ * 880. Decoded String at Index
+ *
+ * An encoded string S is given.  To find and write the decoded string to a tape,
+ * the encoded string is read one character at a time and the following steps are taken:
+ * If the character read is a letter, that letter is written onto the tape.
+ * If the character read is a digit (say d), the entire current tape is repeatedly written d-1 more times in total.
+ * Now for some encoded string S, and an index K, find and return the K-th letter (1 indexed) in the decoded string.
+ *
+ * Example 1:
+ * Input: S = "leet2code3", K = 10
+ * Output: "o"
+ * Explanation:
+ * The decoded string is "leetleetcodeleetleetcodeleetleetcode".
+ * The 10th letter in the string is "o".
+ *
+ * Example 2:
+ * Input: S = "ha22", K = 5
+ * Output: "h"
+ * Explanation:
+ * The decoded string is "hahahaha".  The 5th letter is "h".
+ *
+ * Example 3:
+ * Input: S = "a2345678999999999999999", K = 1
+ * Output: "a"
+ * Explanation:
+ * The decoded string is "a" repeated 8301530446056247680 times.  The 1st letter is "a".
+ *
+ * Note:
+ * 2 <= S.length <= 100
+ * S will only contain lowercase letters and digits 2 through 9.
+ * S starts with a letter.
+ * 1 <= K <= 10^9
+ * The decoded string is guaranteed to have less than 2^63 letters.
+ * */
+public class _880 {
+    public static class Solution1 {
+        public String decodeAtIndex(String S, int K) {
+            //TODO: implement it
+            return "";
+        }
+    }
+}
diff --git a/src/test/java/com/fishercoder/_880Test.java b/src/test/java/com/fishercoder/_880Test.java
@@ -0,0 +1,44 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._880;
+import org.junit.BeforeClass;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+@Ignore
+public class _880Test {
+    private static _880.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _880.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals("o", solution1.decodeAtIndex("leet2code3", 10));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals("h", solution1.decodeAtIndex("ha22", 5));
+    }
+
+    @Test
+    public void test3() {
+        assertEquals("a", solution1.decodeAtIndex("a2345678999999999999999", 1));
+    }
+
+    @Test
+    public void test4() {
+        assertEquals("a", solution1.decodeAtIndex("abc", 1));
+    }
+
+    @Test
+    public void test5() {
+        assertEquals("a", solution1.decodeAtIndex("a2b3c4d5e6f7g8h9", 10));
+    }
+
+}
