week33: nkw601

BOJ/[1253] 좋다/nkw601/Main.java

@@ -0,0 +1,53 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+
+public class Main {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        int N = Integer.parseInt(br.readLine());
+        int[] numbers = new int[N];
+
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < N; i++) {
+            numbers[i] = Integer.parseInt(st.nextToken());
+        }
+
+        Arrays.sort(numbers);
+
+        int ans = 0;
+
+        for (int i = 0; i < N; i++) {
+            int target = numbers[i];
+            int left = 0;
+            int right = N - 1;
+
+            while (left < right) {
+                if (left == i) {
+                    left++;
+                    continue;
+                }
+                if (right == i) {
+                    right--;
+                    continue;
+                }
+
+                int sum = numbers[left] + numbers[right];
+
+                if (sum == target) {
+                    ans++;
+                    break;
+                } else if (sum < target) {
+                    left++;
+                } else {
+                    right--;
+                }
+            }
+        }
+
+        System.out.println(ans);
+    }
+}

BOJ/[1446] 지름길/nkw601/Main.java

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+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.PriorityQueue;
+import java.util.StringTokenizer;
+
+public class Main {
+    private static int N, D;
+    private static int[] dist;
+    private static ArrayList<int[]>[] arrList;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        N = Integer.parseInt(st.nextToken()); // 지름길 개수
+        D = Integer.parseInt(st.nextToken()); // 도착 거리
+
+        dist = new int[D + 1];
+        arrList = new ArrayList[D + 1];
+
+        for (int i = 0; i <= D; i++) {
+            arrList[i] = new ArrayList<>();
+        }
+
+        Arrays.fill(dist, Integer.MAX_VALUE);
+
+        // 원래 도로 추가
+        for (int i = 0; i < D; i++) {
+            arrList[i].add(new int[] { i + 1, 1 });
+        }
+
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            int from = Integer.parseInt(st.nextToken());
+            int to = Integer.parseInt(st.nextToken());
+            int cost = Integer.parseInt(st.nextToken());
+
+            // 볼 가치 확인
+            if (to > D)
+                continue;
+            if (cost >= to - from)
+                continue;
+
+            arrList[from].add(new int[] { to, cost });
+        }
+
+        dijkstra(arrList, dist);
+
+        System.out.println(dist[D]);
+    }
+
+    private static void dijkstra(ArrayList<int[]>[] adjList, int[] dist) {
+        PriorityQueue<int[]> pq = new PriorityQueue<>((o1, o2) -> Integer.compare(o1[1], o2[1]));
+
+        dist[0] = 0;
+        pq.offer(new int[] { 0, 0 });
+
+        while (!pq.isEmpty()) {
+            int[] cur = pq.poll();
+            int curV = cur[0];
+            int curD = cur[1];
+
+            if (curD > dist[curV])
+                continue;
+
+            for (int[] edge : adjList[curV]) {
+                int next = edge[0];
+                int nextDist = curD + edge[1];
+
+                if (nextDist < dist[next]) {
+                    dist[next] = nextDist;
+                    pq.offer(new int[] { next, nextDist });
+                }
+            }
+        }
+    }
+}

BOJ/[20922] 겹치는 건 싫어/nkw601/Main.java

@@ -0,0 +1,40 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        int N = Integer.parseInt(st.nextToken());
+        int K = Integer.parseInt(st.nextToken());
+
+        int[] arr = new int[N];
+        // 등장 횟수
+        int[] count = new int[100001];
+
+        st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < N; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+        }
+
+        int left = 0;
+        int ans = 0;
+
+        for (int right = 0; right < N; right++) {
+            // right 한 칸 앞 -> 숫자 등장
+            count[arr[right]]++;
+            // K번보다 많이 나오면
+            while (count[arr[right]] > K) {
+                // 최장연속수열 불가능
+                count[arr[left]]--;
+                left++;
+            }
+
+            // 길이 갱신하기
+            ans = Math.max(ans, right - left + 1);
+        }
+
+        System.out.println(ans);
+    }
+}