solve: 프로그래머스 문제 풀이 - 3일차

Author: OhChangEun

2025-08-15/오창은/[solved] 프로그래머스_롤케이크 자르기.java

@@ -0,0 +1,31 @@
+import java.util.*;
+
+class Solution {
+    public int solution(int[] topping) {
+        int n = topping.length;
+        
+        int[] leftCount = new int[n];
+        int[] rightCount = new int[n];
+        
+        Map<Integer, Integer> leftMap = new HashMap<>();
+     	for (int i=0; i<n; i++) {
+            leftMap.put(topping[i], leftMap.getOrDefault(topping[i], 0) + 1);
+            leftCount[i] = leftMap.size();
+        }
+        
+        Map<Integer, Integer> rightMap = new HashMap<>();
+     	for (int i=n-1; i>=0; i--) {
+            rightMap.put(topping[i], rightMap.getOrDefault(topping[i], 0) + 1);
+            rightCount[i] = rightMap.size();
+        }
+       
+        int count = 0;
+        for (int i=0; i<n-1; i++) {
+            if (leftCount[i] == rightCount[i+1]) {
+      			count++; 
+            }
+        }
+        
+        return count;
+    }
+}

2025-08-15/오창은/[solved] 프로그래머스_전화번호 목록.java

@@ -0,0 +1,16 @@
+import java.util.*;
+
+class Solution {
+    public boolean solution(String[] phone_book) {
+        boolean answer = true;
+       
+        Arrays.sort(phone_book);
+        
+        for (int i=1; i<phone_book.length; i++) {
+            if (phone_book[i].startsWith(phone_book[i-1]))
+                return false;
+        }
+        
+        return true;
+    }
+}

2025-08-15/오창은/[solved] 프로그래머스_프로세스.java

@@ -0,0 +1,39 @@
+import java.util.*;
+
+class Solution {
+    public int solution(int[] priorities, int location) {
+        int answer = 0;
+     
+        int size = priorities.length;
+        
+        // arr[] = {인덱스, 우선순위}
+        int[] arr = new int[size];
+        Queue<int[]> queue = new LinkedList<>();
+       	PriorityQueue<Integer> pq = new PriorityQueue<>(Collections.reverseOrder()); 
+        for (int i=0; i<size; i++) {
+            queue.offer(new int[]{i, priorities[i]});
+       		pq.offer(priorities[i]); 
+        }
+        
+        while (!pq.isEmpty()) {
+            int[] process = queue.poll();
+            int priority = pq.peek();
+           
+            // 우선순위가 가장 높으면
+            if (process[1] == priority) {
+                pq.poll();
+                answer++;
+                if (process[0] == location) {
+					break;	
+                }
+            } else {
+                // 우선순위가 높은게 아니라면 가장 뒤로
+                queue.offer(process);
+            }
+        }
+        
+        // System.out.println(pq);
+        
+        return answer;
+    }
+}