Added tasks 3309-3312

src/main/java/g3301_3400/s3309_maximum_possible_number_by_binary_concatenation/Solution.java

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+package g3301_3400.s3309_maximum_possible_number_by_binary_concatenation;
+
+// #Medium #Array #Bit_Manipulation #Enumeration
+// #2024_10_08_Time_3_ms_(97.01%)_Space_42.2_MB_(90.32%)
+
+public class Solution {
+    private String result = "0";
+
+    public int maxGoodNumber(int[] nums) {
+        boolean[] visited = new boolean[nums.length];
+        StringBuilder sb = new StringBuilder();
+        solve(nums, visited, 0, sb);
+        int score = 0;
+        int val;
+        for (char c : result.toCharArray()) {
+            val = c - '0';
+            score *= 2;
+            score += val;
+        }
+        return score;
+    }
+
+    private void solve(int[] nums, boolean[] visited, int pos, StringBuilder sb) {
+        if (pos == nums.length) {
+            String val = sb.toString();
+            if ((result.length() == val.length() && result.compareTo(val) < 0)
+                    || val.length() > result.length()) {
+                result = val;
+            }
+            return;
+        }
+        String cur;
+        for (int i = 0; i < nums.length; ++i) {
+            if (visited[i]) {
+                continue;
+            }
+            visited[i] = true;
+            cur = Integer.toBinaryString(nums[i]);
+            sb.append(cur);
+            solve(nums, visited, pos + 1, sb);
+            sb.setLength(sb.length() - cur.length());
+            visited[i] = false;
+        }
+    }
+}

src/main/java/g3301_3400/s3309_maximum_possible_number_by_binary_concatenation/readme.md

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+3309\. Maximum Possible Number by Binary Concatenation
+
+Medium
+
+You are given an array of integers `nums` of size 3.
+
+Return the **maximum** possible number whose _binary representation_ can be formed by **concatenating** the _binary representation_ of **all** elements in `nums` in some order.
+
+**Note** that the binary representation of any number _does not_ contain leading zeros.
+
+**Example 1:**
+
+**Input:** nums = [1,2,3]
+
+**Output:** 30
+
+**Explanation:**
+
+Concatenate the numbers in the order `[3, 1, 2]` to get the result `"11110"`, which is the binary representation of 30.
+
+**Example 2:**
+
+**Input:** nums = [2,8,16]
+
+**Output:** 1296
+
+**Explanation:**
+
+Concatenate the numbers in the order `[2, 8, 16]` to get the result `"10100010000"`, which is the binary representation of 1296.
+
+**Constraints:**
+
+*   `nums.length == 3`
+*   `1 <= nums[i] <= 127`

src/main/java/g3301_3400/s3310_remove_methods_from_project/Solution.java

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+package g3301_3400.s3310_remove_methods_from_project;
+
+// #Medium #Graph #Depth_First_Search #Breadth_First_Search
+// #2024_10_08_Time_41_ms_(99.76%)_Space_154.8_MB_(55.29%)
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Solution {
+    private int[][] graph;
+    private boolean[] suspicious;
+    private boolean[] visited;
+
+    public List<Integer> remainingMethods(int n, int k, int[][] invocations) {
+        pack(invocations, n);
+        suspicious = new boolean[n];
+        visited = new boolean[n];
+        dfs(k, true);
+        Arrays.fill(visited, false);
+        for (int i = 0; i < n; i++) {
+            if (!suspicious[i] && dfs2(i)) {
+                Arrays.fill(visited, false);
+                dfs(k, false);
+                break;
+            }
+        }
+        ArrayList<Integer> rst = new ArrayList<>();
+        for (int i = 0; i < n; i++) {
+            if (!suspicious[i]) {
+                rst.add(i);
+            }
+        }
+        return rst;
+    }
+
+    public void dfs(int u, boolean sus) {
+        if (visited[u]) {
+            return;
+        }
+        visited[u] = true;
+        suspicious[u] = sus;
+        for (int v : graph[u]) {
+            dfs(v, sus);
+        }
+    }
+
+    public boolean dfs2(int u) {
+        if (suspicious[u]) {
+            return true;
+        }
+        if (visited[u]) {
+            return false;
+        }
+        visited[u] = true;
+        for (int v : graph[u]) {
+            if (dfs2(v)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private void pack(int[][] edges, int n) {
+        int[] adj = new int[n];
+        for (int[] edge : edges) {
+            adj[edge[0]]++;
+        }
+        graph = new int[n][];
+        for (int i = 0; i < n; i++) {
+            graph[i] = new int[adj[i]];
+        }
+        for (int[] edge : edges) {
+            graph[edge[0]][--adj[edge[0]]] = edge[1];
+        }
+    }
+}

src/main/java/g3301_3400/s3310_remove_methods_from_project/readme.md

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+3310\. Remove Methods From Project
+
+Medium
+
+You are maintaining a project that has `n` methods numbered from `0` to `n - 1`.
+
+You are given two integers `n` and `k`, and a 2D integer array `invocations`, where <code>invocations[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> indicates that method <code>a<sub>i</sub></code> invokes method <code>b<sub>i</sub></code>.
+
+There is a known bug in method `k`. Method `k`, along with any method invoked by it, either **directly** or **indirectly**, are considered **suspicious** and we aim to remove them.
+
+A group of methods can only be removed if no method **outside** the group invokes any methods **within** it.
+
+Return an array containing all the remaining methods after removing all the **suspicious** methods. You may return the answer in _any order_. If it is not possible to remove **all** the suspicious methods, **none** should be removed.
+
+**Example 1:**
+
+**Input:** n = 4, k = 1, invocations = [[1,2],[0,1],[3,2]]
+
+**Output:** [0,1,2,3]
+
+**Explanation:**
+
+![](https://assets.leetcode.com/uploads/2024/07/18/graph-2.png)
+
+Method 2 and method 1 are suspicious, but they are directly invoked by methods 3 and 0, which are not suspicious. We return all elements without removing anything.
+
+**Example 2:**
+
+**Input:** n = 5, k = 0, invocations = [[1,2],[0,2],[0,1],[3,4]]
+
+**Output:** [3,4]
+
+**Explanation:**
+
+![](https://assets.leetcode.com/uploads/2024/07/18/graph-3.png)
+
+Methods 0, 1, and 2 are suspicious and they are not directly invoked by any other method. We can remove them.
+
+**Example 3:**
+
+**Input:** n = 3, k = 2, invocations = [[1,2],[0,1],[2,0]]
+
+**Output:** []
+
+**Explanation:**
+
+![](https://assets.leetcode.com/uploads/2024/07/20/graph.png)
+
+All methods are suspicious. We can remove them.
+
+**Constraints:**
+
+*   <code>1 <= n <= 10<sup>5</sup></code>
+*   `0 <= k <= n - 1`
+*   <code>0 <= invocations.length <= 2 * 10<sup>5</sup></code>
+*   <code>invocations[i] == [a<sub>i</sub>, b<sub>i</sub>]</code>
+*   <code>0 <= a<sub>i</sub>, b<sub>i</sub> <= n - 1</code>
+*   <code>a<sub>i</sub> != b<sub>i</sub></code>
+*   `invocations[i] != invocations[j]`

src/main/java/g3301_3400/s3311_construct_2d_grid_matching_graph_layout/Solution.java

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+package g3301_3400.s3311_construct_2d_grid_matching_graph_layout;
+
+// #Hard #Array #Hash_Table #Matrix #Graph #2024_10_08_Time_43_ms_(94.34%)_Space_103.6_MB_(79.25%)
+
+import java.util.ArrayList;
+
+@SuppressWarnings("unchecked")
+public class Solution {
+    public int[][] constructGridLayout(int n, int[][] edges) {
+        final int[] cs = new int[n];
+        final ArrayList<Integer>[] als = new ArrayList[n];
+        for (int i = 0; i < n; ++i) {
+            als[i] = new ArrayList<>();
+        }
+        for (int[] e : edges) {
+            cs[e[0]]++;
+            cs[e[1]]++;
+            als[e[0]].add(e[1]);
+            als[e[1]].add(e[0]);
+        }
+        int min = 4;
+        for (int a : cs) {
+            min = Math.min(min, a);
+        }
+        final boolean[] seen = new boolean[n];
+        int[][] res;
+        int st = 0;
+        for (int i = 0; i < n; ++i) {
+            if (cs[i] == min) {
+                st = i;
+                break;
+            }
+        }
+        if (min == 1) {
+            res = new int[1][n];
+            for (int i = 0; i < n; ++i) {
+                res[0][i] = st;
+                seen[st] = true;
+                if (i + 1 < n) {
+                    for (int a : als[st]) {
+                        if (!seen[a]) {
+                            st = a;
+                            break;
+                        }
+                    }
+                }
+            }
+            return res;
+        }
+        int row2 = -1;
+        for (int a : als[st]) {
+            if (cs[a] == min) {
+                row2 = a;
+                break;
+            }
+        }
+        if (row2 >= 0) {
+            return getInts(n, st, row2, seen, als);
+        }
+        return getInts(n, seen, st, als, cs);
+    }
+
+    private int[][] getInts(int n, boolean[] seen, int st, ArrayList<Integer>[] als, int[] cs) {
+        int[][] res;
+        final ArrayList<Integer> al = new ArrayList<>();
+        boolean f = true;
+        seen[st] = true;
+        al.add(st);
+        while (f) {
+            f = false;
+            for (int a : als[st]) {
+                if (!seen[a] && cs[a] <= 3) {
+                    seen[a] = true;
+                    al.add(a);
+                    if (cs[a] == 3) {
+                        f = true;
+                        st = a;
+                    }
+                    break;
+                }
+            }
+        }
+        res = new int[n / al.size()][al.size()];
+        for (int i = 0; i < res[0].length; ++i) {
+            res[0][i] = al.get(i);
+        }
+        for (int i = 1; i < res.length; ++i) {
+            for (int j = 0; j < res[0].length; ++j) {
+                for (int a : als[res[i - 1][j]]) {
+                    if (!seen[a]) {
+                        res[i][j] = a;
+                        seen[a] = true;
+                        break;
+                    }
+                }
+            }
+        }
+        return res;
+    }
+
+    private int[][] getInts(int n, int st, int row2, boolean[] seen, ArrayList<Integer>[] als) {
+        int[][] res;
+        res = new int[2][n / 2];
+        res[0][0] = st;
+        res[1][0] = row2;
+        seen[st] = seen[row2] = true;
+        for (int i = 1; i < res[0].length; ++i) {
+            for (int a : als[res[0][i - 1]]) {
+                if (!seen[a]) {
+                    res[0][i] = a;
+                    seen[a] = true;
+                    break;
+                }
+            }
+            for (int a : als[res[1][i - 1]]) {
+                if (!seen[a]) {
+                    res[1][i] = a;
+                    seen[a] = true;
+                    break;
+                }
+            }
+        }
+        return res;
+    }
+}