[최원준] Day03

leetcode2/1easy/최원준/Q2511.java

@@ -0,0 +1,64 @@
+package Leetcode.최원준;
+
+/*
+1. 아이디어 :
+
+
+2. 시간복잡도 :
+O( )
+
+3. 자료구조/알고리즘 :
+
+ */
+
+public class Q2511 {
+    class Solution {
+        public int captureForts(int[] forts) {
+            int n = forts.length;
+
+            int ans = 0;
+            int curr = -n;
+            boolean found = false;
+            for (int i=0; i<n; i++) {
+                if (forts[i] == 1) {
+                    found = true;
+                    curr = 0;
+                }
+
+                if (forts[i] == 0 && found) {
+                    curr++;
+                }
+
+                if (forts[i] == -1) {
+                    if (found) {
+                        ans = Math.max(ans, curr);
+                    }
+                    curr = 0;
+                    found = false;
+                }
+            }
+
+            curr = -n;
+            found = false;
+            for (int i=n-1; i>-1; i--) {
+                if (forts[i] == 1) {
+                    found = true;
+                    curr = 0;
+                }
+
+                if (forts[i] == 0 && found) {
+                    curr++;
+                }
+
+                if (forts[i] == -1) {
+                    if (found) {
+                        ans = Math.max(ans, curr);
+                    }
+                    curr = 0;
+                    found = false;
+                }
+            }
+            return ans;
+        }
+    }
+}

leetcode2/2medium/최원준/Q3310.java

@@ -0,0 +1,80 @@
+package Leetcode.최원준;
+
+/*
+1. 아이디어 :
+
+
+2. 시간복잡도 :
+O( )
+
+3. 자료구조/알고리즘 :
+
+ */
+
+import java.util.*;
+
+public class Q3310 {
+    class Solution {
+        int[] par;
+
+        public List<Integer> remainingMethods(int n, int k, int[][] invocations) {
+            par = new int[n];
+            for (int i=0; i<n; i++) par[i] = i;
+
+            Map<Integer, List<Integer>> invokes = new HashMap<>();
+            for (int[] i : invocations) {
+                invokes.putIfAbsent(i[0], new ArrayList<>());
+                invokes.get(i[0]).add(i[1]);
+            }
+
+            Deque<Integer> deque = new ArrayDeque<>();
+            boolean[] visited = new boolean[n];
+            visited[k] = true;
+            deque.add(k);
+
+            while (!deque.isEmpty()) {
+                int curr = deque.pollFirst();
+
+                for (int neighbor : invokes.getOrDefault(curr, new ArrayList<>())) {
+                    if (visited[neighbor]) continue;
+                    visited[neighbor] = true;
+                    deque.add(neighbor);
+                    union(curr, neighbor);
+                }
+            }
+
+            for (int i=0; i<n; i++) {
+                int curr = find(i);
+                if (visited[curr]) continue;
+                for (int neighbor : invokes.getOrDefault(curr, new ArrayList<>())) {
+                    int rootNeighbor = find(neighbor);
+                    visited[rootNeighbor] = false;
+                }
+            }
+
+            List<Integer> ans = new ArrayList<>();
+            for (int i=0; i<n; i++) {
+                if (!visited[find(i)]) ans.add(i);
+            }
+
+            return ans;
+        }
+
+        public int find(int a) {
+            if (par[a] != a) par[a] = find(par[a]);
+            return par[a];
+        }
+
+        public boolean union(int a, int b) {
+            int ra = find(a), rb = find(b);
+            if (ra == rb) return true;
+
+            if (ra > rb) {
+                par[rb] = ra;
+            } else {
+                par[ra] = rb;
+            }
+            return false;
+        }
+    }
+}