[20250507] BOJ / D5 / Strike Zone / 신희을

ShinHeeEul/202505/07 BOJ D5 Strike Zone.md

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+```java
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+
+class Main {
+
+
+    static int N;
+    static int size;
+    static Node[] segments;
+    static Point[] arr;
+    static long D_MIN = Long.MIN_VALUE >> 1;
+    static Node DEFAULT = new Node(D_MIN, D_MIN, D_MIN, 0);
+
+    public static void main(String[] args) throws Exception {
+
+        N = read();
+
+        ArrayList<Point> list = new ArrayList<>();
+
+        for(int i = 0; i < N; i++) {
+            list.add(new Point (read(), read(), 1));
+        }
+
+        int M = read();
+
+        for(int i = 0; i < M; i++) {
+            list.add(new Point(read(), read(), -1));
+        }
+
+
+        int S = read();
+        int E = read();
+
+
+        arr = list.toArray(new Point[0]);
+
+        for(int i = 0; i < N; i++) arr[i].val *= S;
+        for(int i = N; i < N + M; i++) arr[i].val *= E;
+
+
+        N += M;
+
+
+        // x좌표가 작은 순으로 정렬
+        Arrays.sort(arr, (o1, o2) -> {
+            if(o1.x == o2.x) return o1.y - o2.y;
+            return o1.x - o2.x;
+        });
+
+
+        int cnt = 1;
+        for(int i = 0; i < N; i++) {
+            arr[i].index = cnt;
+            while(i != N - 1 && arr[i].x == arr[i + 1].x) {
+                arr[i + 1].index = cnt;
+                i++;
+            }
+            cnt++;
+        }
+
+        size = 1;
+
+        while(size < cnt) size <<= 1;
+
+        Arrays.sort(arr, Comparator.comparingInt(o -> o.y));
+
+
+        long max = S;
+        for(int i = 0; i < N; i++) {
+
+            // y가 같으면 보지 않아야 됨
+            int start = i;
+            while(i != N-1 && arr[i].y == arr[i + 1].y) {
+                i++;
+            }
+
+            segments = new Node[(size << 1) + 1];
+            Arrays.fill(segments,DEFAULT);
+
+            for(int j = start; j < N; j++) {
+                update(arr[j].index, arr[j].val);
+                while(j != N - 1 && arr[j].y == arr[j + 1].y) {
+                    update(arr[j + 1].index, arr[j + 1].val);
+                    j++;
+                }
+                // 업데이트 치고 max 찾고
+                max = Math.max(max, segments[2].max);
+            }
+
+        }
+
+        System.out.println(max);
+    }
+
+    static void update(int index, long val) {
+        index += size;
+
+        if(segments[index] == DEFAULT) {
+            segments[index] = new Node(val, val, val, val);
+        } else {
+            segments[index].rmax += val;
+            segments[index].lmax += val;
+            segments[index].max += val;
+            segments[index].sum += val;
+        }
+
+        index = (index + 1) >> 1;
+        while(index >= 2) {
+            segments[index] = combine(segments[(index << 1) - 1], segments[index << 1]);
+            index = (index + 1) >> 1;
+        }
+    }
+
+    static Node combine(Node lNode, Node rNode) {
+        return new Node(
+                Math.max(lNode.lmax, lNode.sum + rNode.lmax),
+                Math.max(rNode.rmax, rNode.sum + lNode.rmax),
+                Math.max(lNode.rmax + rNode.lmax, Math.max(lNode.max, rNode.max)),
+                rNode.sum + lNode.sum
+        );
+    }
+
+    static class Node {
+        long rmax;
+        long lmax;
+        long max;
+        long sum;
+
+        public Node(long lmax, long rmax,long max, long sum) {
+            this.rmax = rmax;
+            this.lmax = lmax;
+            this.max = max;
+            this.sum = sum;
+        }
+    }
+
+    static class Point {
+        int x;
+        int y;
+        int val;
+        int index;
+
+        public Point(int x, int y, int val) {
+            this.x = x;
+            this.y = y;
+            this.val = val;
+        }
+    }
+
+    private static int read() throws Exception {
+        int d, o;
+        boolean negative = false;
+
+        while (true) {
+            d = System.in.read();
+            if (d == -1) return -1; // EOF
+            if (!Character.isWhitespace(d)) break;
+        }
+
+        // 음수 처리
+        if (d == '-') {
+            negative = true;
+            d = System.in.read();
+        }
+
+        o = d & 15;
+        while (true) {
+            d = System.in.read();
+            if (d == -1 || Character.isWhitespace(d)) break;
+            o = (o << 3) + (o << 1) + (d & 15);
+        }
+
+        return negative ? -o : o;
+    }
+
+
+}
+```