Merge pull request #1111 from AlgorithmWithGod/Ukj0ng

[20251014] BOJ / G4 / 고냥이 / 한종욱

Author: ShinHeeEul

Ukj0ng/202510/14 BOJ G4 고냥이.md

@@ -0,0 +1,58 @@
+```
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static Map<Character, Integer> map;
+    private static char[] input;
+    private static int N;
+    public static void main(String[] args) throws IOException {
+        init();
+
+        int answer = twoPointer();
+
+        bw.write(answer + "\n");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        N = Integer.parseInt(br.readLine());
+        map = new HashMap<>();
+        input = br.readLine().toCharArray();
+    }
+
+    private static int twoPointer() {
+        int left = 0;
+        int right = 0;
+        int max = 0;
+        int count = 0;
+
+        while (left < input.length) {
+            if (right < input.length && valid(input[right])) {
+                map.put(input[right], map.getOrDefault(input[right], 0)+1);
+                count++;
+                max = Math.max(max, count);
+                right++;
+            } else {
+                map.put(input[left], map.get(input[left])-1);
+                if (map.get(input[left]) == 0) {
+                    map.remove(input[left]);
+                }
+                left++;
+                count--;
+            }
+        }
+
+        return max;
+    }
+
+    private static boolean valid(char c) {
+        return (map.containsKey(c) && map.size() <= N) || (!map.containsKey(c) && map.size() < N);
+    }
+
+}
+```