diff --git a/programmers/[1차] 캐시/solution.java b/programmers/[1차] 캐시/solution.java
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+++ b/programmers/[1차] 캐시/solution.java	
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+// [문제 링크]: https://school.programmers.co.kr/learn/courses/30/lessons/17680
+
+import java.util.HashMap;
+class Solution {
+    public int solution(int cacheSize, String[] cities) {
+        HashMap<Integer,String> hs = new HashMap<>();
+        HashMap<Integer,Integer> hss = new HashMap<>();
+        int[] hsA = new int[cities.length];
+        int answer = 0, aIdx = 0, hit = 1, miss = 5, oa = 1;
+        boolean cc = false;
+        for(String c : cities){
+            c = c.toLowerCase();
+            int ccon = 0;
+            if(cacheSize == 0){
+                answer += miss;
+                continue;
+            }
+            while(cc==false){
+                // for(int a = 1; a <= cacheSize; a ++){
+                //     if(hs.get(a) == null) {
+                        int bcon = 0;
+                        for(int cs = 1; cs <= Math.min(cacheSize, aIdx); cs ++){
+                            if(hs.getOrDefault(hsA[aIdx-cs],"").equals(c)){
+                                int x = hsA[aIdx-cs];
+                                hs.put(x,c);
+                                hss.put(x,aIdx);
+                                for(int cb = aIdx-cs; cb > Math.max(aIdx - cacheSize,0); cb--){
+                                    // hss.put(hsA[cb-1],cb);
+                                    hsA[cb]=hsA[cb-1];
+                                }
+                                
+                // System.out.println(aIdx+" "+x+" 초기중복");
+                                hsA[aIdx++]=x;
+                                answer += hit;
+                                bcon = 1;
+                                // oa--;
+                                break;
+                            }
+                        }
+                        if(bcon != 0) break;
+                        ccon = oa;
+                        hs.put(oa,c);
+                        hss.put(oa,aIdx);
+                // System.out.println(aIdx+" "+oa+" 최초키입력");
+                        hsA[aIdx++]=oa;
+                        answer += miss;
+                        if(oa++==cacheSize) cc = true;
+                        break;
+                //     }
+                // } // aIdx > cacheSize-1
+            }
+            if(ccon == 0 && cc){
+                int con = 0;
+                for(int cs = 1; cs <= cacheSize; cs++){
+                    int a = cs;
+                    if(hs.getOrDefault(hsA[aIdx-cs],"").equals(c)){
+                        a = hsA[aIdx-cs];
+                        con = a;
+                        hs.put(a,c);
+                        hss.put(a,aIdx);
+                        for(int cb = aIdx-cs; cb > aIdx - cacheSize; cb--){
+                            hss.put(hsA[cb-1],cb);
+                            hsA[cb]=hsA[cb-1];
+                        }
+                        hsA[aIdx++]=a;
+                        answer += hit;
+                        break;
+                    } 
+                }
+                if(con==0){
+                    int min = hss.get(1), mina = 1;
+                    for(int a = 1; a <= cacheSize; a++){
+                        if(min > Math.min(hss.get(a),min)){
+                            min = Math.min(hss.get(a),min);
+                            mina = a;
+                        }
+                    }       //     - for
+                    // if(hss.get(a)==aIdx-cacheSize){
+                        hs.put(mina,c);
+                        hss.put(mina,aIdx);
+                        // System.out.println(aIdx+" "+mina+" 교체");
+                        hsA[aIdx++]=mina;
+                        answer += miss;
+                        // break;
+                    // }
+                }           // if not matched
+            }               // if Last
+        }                   //Main for
+    return answer;
+    }
+}
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