[Week05] BOJ 14002: 가장 긴 증가하는 부분 수열4

[Week05] BOJ 14002: 가장 긴 증가하는 부분 수열4

Author: sukangpunch

weekly/week05/BOJ_14002_가장긴증가하는부분수열4/sukangpunch.java

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+package study.week05;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.Stack;
+
+// 가장 긴 증가하는 부분 수열4
+public class BOJ_14002 {
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringBuilder sb = new StringBuilder();
+
+        int N = Integer.parseInt(br.readLine());
+
+        int [] arr = new int[N];
+        String []s = br.readLine().split(" ");
+
+        for(int i=0; i<N; i++){
+            arr[i] = Integer.parseInt(s[i]);
+        }
+
+        int [] dp = new int[N];
+        int [] pre = new int[N];
+        Arrays.fill(dp, 1);
+        pre[0] = 0;
+
+        for(int i=1; i<N; i++){
+            for(int j=0; j < i; j++){
+                if(arr[i] > arr[j]){
+                    if(dp[i] < dp[j] + 1){
+                        dp[i] = dp[j] + 1;
+                        pre[i] = j;
+                    }
+                }else{
+                    if(dp[i] <= 1) {
+                        dp[i] = 1;
+                        pre[i] = i;
+                    }
+                }
+            }
+        }
+
+        int max = 0;
+        int maxIdx = 0;
+        for(int i=0; i<N; i++){
+            if(max < dp[i]){
+                max = dp[i];
+                maxIdx = i;
+            }
+        }
+
+        // 최대 부분수열 길이
+        sb.append(max).append("\n");
+
+        Stack<Integer> st = new Stack<>();
+        st.push(arr[maxIdx]);
+        int tmp = maxIdx;
+
+        while(true){
+            if(tmp == pre[tmp])break;
+            tmp = pre[tmp];
+            st.push(arr[tmp]);
+        }
+
+        while(!st.isEmpty()){
+            sb.append(st.pop()).append(" ");
+        }
+
+        System.out.println(sb);
+    }
+}