[최원준]Day07

leetcode2/1easy/최원준/Q2748.java

@@ -0,0 +1,47 @@
+package Leetcode.최원준;
+
+/*
+1. 아이디어 :
+
+
+2. 시간복잡도 :
+O( )
+
+3. 자료구조/알고리즘 :
+
+ */
+
+public class Q2748 {
+    class Solution {
+        public int gcd(int a, int b) {
+            if (b!=0) return gcd(b, a%b);
+            return a;
+        }
+
+        public int getFirstDigit(int num) {
+            while (num >= 10) num /= 10;
+            return num;
+        }
+
+        public int getLastDigit(int num) {
+            return num % 10;
+        }
+
+        public int countBeautifulPairs(int[] nums) {
+            int ans = 0;
+            int n = nums.length;
+            int[][] digits = new int[n][n];
+            for (int i=0; i<n; i++) {
+                digits[i][0] = getFirstDigit(nums[i]);
+                digits[i][1] = getLastDigit(nums[i]);
+            }
+
+            for (int i=0; i<n; i++) for (int j=i+1; j<n; j++) {
+                if (gcd(digits[i][0], digits[j][1]) == 1) ans++;
+            }
+
+
+            return ans;
+        }
+    }
+}

leetcode2/2medium/최원준/Q1297.java

@@ -0,0 +1,54 @@
+package Leetcode.최원준;
+
+/*
+1. 아이디어 :
+
+
+2. 시간복잡도 :
+O( )
+
+3. 자료구조/알고리즘 :
+
+ */
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class Q1297 {
+    class Solution {
+        public boolean check(String key, int maxLetters) {
+            Set<Character> distincts = new HashSet<>();
+            for (char c : key.toCharArray()) {
+                distincts.add(c);
+                if (distincts.size() > maxLetters) return false;
+            }
+            return true;
+        }
+        public int maxFreq(String s, int maxLetters, int minSize, int maxSize) {
+            int n = s.length();
+            Map<String, Integer> counter = new HashMap<>();
+
+            StringBuilder sb = new StringBuilder();
+            for (int i=0; i<minSize; i++) {
+                sb.append(s.charAt(i));
+            }
+            counter.put(sb.toString(), counter.getOrDefault(sb.toString(), 0)+1);
+
+            for (int i=minSize; i<n; i++) {
+                sb.append(s.charAt(i));
+                sb.delete(0, 1);
+                counter.put(sb.toString(), counter.getOrDefault(sb.toString(), 0)+1);
+            }
+
+            int ans = 0;
+            for (var entry : counter.entrySet()) {
+                if (check(entry.getKey(), maxLetters)) {
+                    ans = Math.max(ans, entry.getValue());
+                }
+            }
+            return ans;
+        }
+    }
+}