issue #44 2565 전깃줄

sowon-dev · sowon-dev · commit f8bbad44a99b · 2021-07-15T07:01:28.000+09:00
diff --git a/src/backjoon/_2565.java b/src/backjoon/_2565.java
@@ -0,0 +1,52 @@
+package backjoon;
+// https://www.acmicpc.net/problem/2565
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.StringTokenizer;
+
+public class _2565 {
+  public static void main(String[] args) throws IOException {
+
+    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    int N = Integer.parseInt(br.readLine());
+
+    int[][] firstWire = new int[N][2];
+    int[] dp = new int[N];
+
+    StringTokenizer st;
+    for(int i = 0; i < firstWire.length; i++) {
+      st = new StringTokenizer(br.readLine()," ");
+      firstWire[i][0] = Integer.parseInt(st.nextToken());
+      firstWire[i][1] = Integer.parseInt(st.nextToken());
+    }
+
+    // 왼쪽 전봇대를 기준으로 2차원 배열 정렬
+    Arrays.sort(firstWire, new Comparator <int[]>() {
+      @Override
+      public int compare(int[] o1, int[] o2) {
+        return o1[0] - o2[0];
+      }
+    });
+
+    for(int i=0; i<dp.length; i++){
+      dp[i] = 1;
+      for(int j=0; j<i; j++){
+        if(firstWire[i][1] > firstWire[j][1]){
+          dp[i] = Math.max(dp[i], dp[j]+1);
+        }
+      }
+    }
+
+    int max = 0;
+    for(int i=0; i<N; i++){
+      max = Math.max(max, dp[i]);
+    }
+
+    // 전체 전선 개수 - 최대 설치가능 개수 = 최소 철거가능 개수
+    System.out.println(N-max);
+  }
+}
