Added task 779.

Author: javadev

src/main/java/g0701_0800/s0779_k_th_symbol_in_grammar/Solution.java

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+package g0701_0800.s0779_k_th_symbol_in_grammar;
+
+// #Medium #Math #Bit_Manipulation #Recursion
+
+@SuppressWarnings("java:S1172")
+public class Solution {
+    /*
+     * Time: O(logn)
+     * Space: O(1)
+     */
+    public int kthGrammar(int n, int k) {
+        return Integer.bitCount(k - 1) % 2;
+    }
+}

src/main/java/g0701_0800/s0779_k_th_symbol_in_grammar/readme.md

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+779\. K-th Symbol in Grammar
+
+Medium
+
+We build a table of `n` rows (**1-indexed**). We start by writing `0` in the <code>1<sup>st</sup></code> row. Now in every subsequent row, we look at the previous row and replace each occurrence of `0` with `01`, and each occurrence of `1` with `10`.
+
+*   For example, for `n = 3`, the <code>1<sup>st</sup></code> row is `0`, the <code>2<sup>nd</sup></code> row is `01`, and the <code>3<sup>rd</sup></code> row is `0110`.
+
+Given two integer `n` and `k`, return the <code>k<sup>th</sup></code> (**1-indexed**) symbol in the <code>n<sup>th</sup></code> row of a table of `n` rows.
+
+**Example 1:**
+
+**Input:** n = 1, k = 1
+
+**Output:** 0
+
+**Explanation:** row 1: 0
+
+**Example 2:**
+
+**Input:** n = 2, k = 1
+
+**Output:** 0
+
+**Explanation:** row 1: 0 row 2: 01
+
+**Example 3:**
+
+**Input:** n = 2, k = 2
+
+**Output:** 1
+
+**Explanation:** row 1: 0 row 2: 01
+
+**Constraints:**
+
+*   `1 <= n <= 30`
+*   <code>1 <= k <= 2<sup>n - 1</sup></code>

src/test/java/g0701_0800/s0779_k_th_symbol_in_grammar/SolutionTest.java

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+package g0701_0800.s0779_k_th_symbol_in_grammar;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class SolutionTest {
+    @Test
+    void kthGrammar() {
+        assertThat(new Solution().kthGrammar(1, 1), equalTo(0));
+    }
+
+    @Test
+    void kthGrammar2() {
+        assertThat(new Solution().kthGrammar(2, 1), equalTo(0));
+    }
+
+    @Test
+    void kthGrammar3() {
+        assertThat(new Solution().kthGrammar(2, 2), equalTo(1));
+    }
+}