백준/단계별: 2565 전깃줄 문제풀이 (#27)

src/baekjoon/step/dynamicProgramming/PROB2565.java

@@ -0,0 +1,48 @@
+package baekjoon.step.dynamicProgramming;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+
+public class PROB2565 {
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static StringTokenizer st;
+    static int N;
+    static int[][] lines;
+    static int[] dp;
+    static int max = Integer.MIN_VALUE;
+
+    public static void main(String[] args) throws IOException {
+        N = Integer.parseInt(br.readLine());
+        lines = new int[N][2];
+        dp = new int[N];
+
+        for (int i = 0; i < N; i ++) {
+            st = new StringTokenizer(br.readLine());
+            lines[i][0] = Integer.parseInt(st.nextToken());
+            lines[i][1] = Integer.parseInt(st.nextToken());
+        }
+
+        Arrays.sort(lines, (int[] o1, int[] o2) -> {
+            return o1[0] - o2[0];
+        });
+
+        dp();
+
+        System.out.println(N - max);
+    }
+
+    public static void dp() {
+        for (int i = 0; i < N; i ++) {
+            dp[i] = 1; // 자기 자신
+            for (int j = 0; j < i; j ++) {
+                if (lines[j][1] < lines[i][1]) { // 현재 전봇대 보다 이전에 있는 전봇대들의 값이 작아야 한다.
+                    dp[i] = Math.max(dp[i], dp[j] + 1);
+                }
+            }
+            max = Math.max(max, dp[i]);
+        }
+    }
+}