[DP] baekjoon-13398

Author: Seogeurim

README.md

@@ -215,6 +215,7 @@
 | 23  |     | [Baekjoon-11722 가장 긴 감소하는 부분 수열](src/DP/P11722) |      |
 | 24  |     | [Baekjoon-11054 가장 긴 바이토닉 부분 수열](src/DP/P11054) |      |
 | 25  |     | [Baekjoon-1912 연속합](src/DP/P1912) |      |
+| 26  |     | [Baekjoon-13398 연속합 2](src/DP/P13398) |      |
 
 ---
 

src/DP/P13398/Main.java

@@ -0,0 +1,34 @@
+package DP.P13398;
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static int n;
+    static int[] arr;
+    static int[][] dp;
+
+    public static void main(String[] args) throws Exception {
+        System.setIn(new FileInputStream("src/DP/P13398/input.txt"));
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        n = Integer.parseInt(br.readLine());
+        arr = new int[n];
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < n; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+        }
+
+        dp = new int[n][2];
+        dp[0][0] = dp[0][1] = arr[0];
+        int max = arr[0];
+        for (int i = 1; i < n; i++) {
+            dp[i][0] = Math.max(dp[i-1][0], 0) + arr[i];
+            dp[i][1] = Math.max(dp[i-1][0], dp[i-1][1] + arr[i]);
+            max = Math.max(max, Math.max(dp[i][0], dp[i][1]));
+        }
+
+        System.out.println(max);
+    }
+}

src/DP/P13398/README.md

@@ -0,0 +1,15 @@
+## [baekjoon-13398] 연속합 2
+
+![image](https://user-images.githubusercontent.com/22045163/100982308-3cb2a900-358b-11eb-9cf0-37de27655ed8.png)
+
+### 점화식
+
+```java
+dp[0][0] = dp[0][1] = arr[0];
+dp[n][0] = Math.max(dp[n-1][0], 0) + arr[n];
+dp[n][1] = Math.max(dp[n-1][0], dp[n-1][1] + arr[n]);
+```
+
+![IMG_BEB4BBF853D3-1](https://user-images.githubusercontent.com/22045163/100983690-00804800-358d-11eb-81a9-2f0c46161d57.jpeg)
+
+후아.. 한참을 헤맨 문제다. 성장하자 !!!

src/DP/P13398/input.txt

@@ -0,0 +1,11 @@
+5
+-10 10 20 -40 50
+
+10
+2 1 -4 3 4 -4 6 5 -5 1
+
+10
+10 -4 3 1 5 6 -35 12 21 -1
+
+5
+-1 -2 -3 -4 -5