[Week02] BOJ: 퇴사 2

personal/JAEHEE25/Programmers/수식_최대화.java

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+import java.util.*;
+class Solution {
+    public long solution(String expression) {
+        List<String> list = toList(expression); //리스트로 분리
+
+        //우선순위별 계산
+        String[] prior = {"*-+", "*+-", "+-*", "+*-", "-*+", "-+*"};
+        long answer = 0;
+        for (String p : prior) {
+            answer = Math.max(getResult(list, p), answer); //해당 우선순위로 계산했을 때의 결과로 최댓값 찾기
+        }
+        return answer;
+    }
+
+    long getResult(List<String> list, String p) {
+        Deque<String> dq = new ArrayDeque<>();
+        for (int i = 0; i < list.size(); i++) { //리스트로 덱 초기화
+            dq.offerLast(list.get(i));
+        }
+        dq.offerLast("last"); //마지막 원소임을 표시
+
+        int pi = 0;
+        char op = '.'; //.으로 초기화
+        while (pi < 3) {
+            String val = dq.pollFirst();
+
+            if (val.equals("last")) { //마지막 원소일 경우
+                pi++;
+                if (dq.size() == 1) { //1개만 남았을 경우 최종 결과 반환
+                    return Math.abs(Long.parseLong(dq.pollLast()));
+                }
+                dq.offerLast("last");
+                continue;
+            }
+
+            if (op != '.') { //계산
+                long num1 = Long.parseLong(dq.pollLast());
+                long num2 = Long.parseLong(val);
+                long result = calculate(num1, num2, op);
+                dq.offerLast(String.valueOf(result)); //연산 결과 삽입
+                op = '.';
+                continue;
+            }
+
+            if (val.charAt(0) == p.charAt(pi)) { //우선순위에 해당하는 연산자라면
+                op = val.charAt(0);
+            } else {
+                dq.offerLast(val);
+            }
+        }
+
+        return 0;
+    }
+
+    long calculate(long num1, long num2, char op) {
+        if (op == '*') {
+            return num1 * num2;
+        } else if (op == '+') {
+            return num1 + num2;
+        } else {
+            return num1 - num2;
+        }
+    }
+
+    List<String> toList(String expression) {
+        List<String> list = new ArrayList<>();
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < expression.length(); i++) {
+            char c = expression.charAt(i);
+            if (!Character.isDigit(c)) { //연산자라면
+                list.add(sb.toString());
+                sb = new StringBuilder();
+                list.add(String.valueOf(c));
+            } else {
+                sb.append(c);
+            }
+        }
+        list.add(sb.toString());
+        return list;
+    }
+}

weekly/week02/BOJ_15486_퇴사2/JAEHEE25.java

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+package week02.BOJ_15486_퇴사2;
+
+import java.util.*;
+import java.lang.*;
+import java.io.*;
+
+class BOJ15486 {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int N = Integer.parseInt(br.readLine());
+        int[] T = new int[N];
+        int[] P = new int[N];
+        for (int i = 0; i < N; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int t = Integer.parseInt(st.nextToken());
+            int p = Integer.parseInt(st.nextToken());
+            T[i] = t;
+            P[i] = p;
+        }
+
+        int max = 0;
+        int[] dp = new int[N + 1];
+        for (int i = 0; i < N; i++) {
+            max = Math.max(dp[i], max);
+            if (i + T[i] <= N) { //기간 초과 제외
+                dp[i + T[i]] = Math.max(P[i] + max, dp[i + T[i]]);
+            }
+        }
+
+        System.out.println(Math.max(dp[N], max));
+    }
+}