BOJ #18436: 수열과 쿼리 37

Author: ISKU

BOJ/18436/Main.java

@@ -0,0 +1,77 @@
+/*
+ * Author: Minho Kim (ISKU)
+ * Date: February 14, 2020
+ * E-mail: minho.kim093@gmail.com
+ *
+ * https://github.com/ISKU/Algorithm
+ * https://www.acmicpc.net/problem/18436
+ */
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+private static int[] tree;
+private static int H;
+
+public static void main(String... args) throws Exception {
+BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+int N = Integer.parseInt(br.readLine());
+
+H = 1 << (int) Math.ceil(Math.log(N) / Math.log(2));
+tree = new int[H * 2];
+StringTokenizer st = new StringTokenizer(br.readLine());
+for (int i = 1; i <= N; i++) {
+int n = Integer.parseInt(st.nextToken());
+update(i, n);
+}
+
+int M = Integer.parseInt(br.readLine());
+while (M-- > 0) {
+st = new StringTokenizer(br.readLine());
+int cmd = Integer.parseInt(st.nextToken());
+
+if (cmd == 1) {
+int i = Integer.parseInt(st.nextToken());
+int x = Integer.parseInt(st.nextToken());
+update(i, x);
+} else if (cmd == 2) {
+int l = Integer.parseInt(st.nextToken());
+int r = Integer.parseInt(st.nextToken());
+int sum = r - l + 1 - sum(1, H, 1, l, r);
+bw.write(String.valueOf(sum));
+bw.write('\n');
+} else if (cmd == 3) {
+int l = Integer.parseInt(st.nextToken());
+int r = Integer.parseInt(st.nextToken());
+int sum = sum(1, H, 1, l, r);
+bw.write(String.valueOf(sum));
+bw.write('\n');
+}
+}
+
+bw.close();
+}
+
+private static void update(int i, int x) {
+i += H - 1;
+tree[i] = x % 2;
+
+while (i > 0) {
+i /= 2;
+tree[i] = tree[i * 2] + tree[i * 2 + 1];
+}
+}
+
+private static int sum(int l, int r, int i, int L, int R) {
+if (r < L || R < l)
+return 0;
+if (L <= l && r <= R)
+return tree[i];
+
+int mid = (l + r) / 2;
+return sum(l, mid, i * 2, L, R) + sum(mid + 1, r, i * 2 + 1, L, R);
+}
+}