week29: nkw601

BOJ/[20920] 영단어 암기는 괴로워/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.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.StringTokenizer;
+
+public class Main {
+	private static int N, M; // 지문에 나오는 단어 수, 외울 단어의 길이 기준(M 이상만 외움)
+	private static HashMap<String, Integer> words;
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		StringBuilder sb = new StringBuilder();
+		// 입력, 초기화
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+		words = new HashMap<>();		
+
+		for(int i = 0; i < N; i++) {
+			String word = br.readLine();
+			// 길이가 M 이상일 때에만 외움
+			if(word.length() >= M) {
+				// getOrDefault
+				words.put(word, words.getOrDefault(word, 0) + 1);
+			}
+		}
+
+		// 자주 나오는 단어면 앞에
+		// 단어의 길이가 길면 앞에
+		// 알파벳 사전 순으로 앞이면 앞에
+		ArrayList<String> wordsList = new ArrayList<>(words.keySet());
+		Collections.sort(wordsList, (o1, o2) -> {
+		    int f1 = words.get(o1), f2 = words.get(o2);
+		    if (f1 != f2) return Integer.compare(f2, f1);      // 빈도
+		    int l1 = o1.length(), l2 = o2.length();
+		    if (l1 != l2) return Integer.compare(l2, l1);      // 길이
+		    return o1.compareTo(o2);                           // 사전순
+		});
+
+
+		for(String word : wordsList) {
+			sb.append(word).append("\n");
+		}
+
+		System.out.println(sb);
+
+	}
+
+}

BOJ/[2512] 예산/nkw601/Main.java

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+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.StringTokenizer;
+
+public class Main {
+    private static int N, M;
+    private static int[] budgets;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        N = Integer.parseInt(br.readLine());
+        budgets = new int[N];
+
+        st = new StringTokenizer(br.readLine());
+        int maxReq = 0;
+        long sum = 0;
+        for (int i = 0; i < N; i++) {
+            budgets[i] = Integer.parseInt(st.nextToken());
+            sum += budgets[i];
+            if (budgets[i] > maxReq) maxReq = budgets[i];
+        }
+
+        M = Integer.parseInt(br.readLine());
+
+        if (sum <= M) {
+            System.out.println(maxReq);
+            return;
+        }
+
+        int low = 0;
+        int high = maxReq;
+        int ans = 0;
+
+        while (low <= high) {
+            int mid = (low + high) / 2;
+            long s = 0;
+
+            for (int b : budgets) {
+                s += (b > mid) ? mid : b;
+            }
+
+            if (s <= M) {
+                ans = mid;
+                low = mid + 1;
+            } else {
+                high = mid - 1;
+            }
+        }
+
+        System.out.println(ans);
+    }
+}

BOJ/[5972] 택배 배송/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, M;
+	private static int[] stovers; // stovers: i번째 헛간까지 도착하는 최소 여물 수
+	private static ArrayList<int[]>[] barns;
+	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());
+		M = Integer.parseInt(st.nextToken());
+
+		// 초기화
+		stovers = new int[N + 1];
+		Arrays.fill(stovers, Integer.MAX_VALUE);
+		barns = new ArrayList[N + 1];
+		for(int i = 1; i <= N; i++) {
+			barns[i] = new ArrayList<>();
+		}
+
+		for(int i = 0; i < M; i++) {
+			st = new StringTokenizer(br.readLine());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			int c = Integer.parseInt(st.nextToken());
+
+			// 인접리스트 만들기
+			barns[a].add(new int[] {b, c});
+			barns[b].add(new int[] {a, c});
+		}
+
+		dijkstra(1, N);
+		System.out.println(stovers[N]);
+	}
+
+
+	private static void dijkstra(int start, int end) {
+		PriorityQueue<int[]> pq = new PriorityQueue<>((o1, o2) -> Integer.compare(o1[1], o2[1]));
+		stovers[start] = 0;
+		pq.offer(new int[] {start, 0});
+
+		while(!pq.isEmpty()) {
+			int[] cur = pq.poll();
+
+			int curBarn = cur[0];
+			int curWei = cur[1];
+
+			if(curWei > stovers[curBarn]) continue; // 방문처리
+
+			for(int[] next : barns[curBarn]) {
+				int nextBarn = next[0];
+				int nextWei = next[1] + curWei;
+
+				if(nextWei < stovers[nextBarn]) {
+					pq.offer(new int[] {nextBarn, nextWei});
+					stovers[nextBarn] = nextWei;
+				}
+			}
+		}
+	}
+}
+/*
+ * 입력
+ * N M
+ * M: A_i B_i C_i
+ * 
+ * 출력
+ * 농부 현서가 가져가야하는 최소 여물
+ * 
+ * 이해
+ * N개의 헛간, M개의 양방향 길
+ * 각각의 길의 가중치 C(소 수)
+ * 
+ * 헛간 1 -> 헛간 N
+ * 
+ * 생각
+ * 최단 거리 with 가중치 -> 다익스트라
+ */