241028 구간 곱 구하기

private static final int MOD = 1_000_000_007;

public static void main(String[] args) throws Exception {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

	StringTokenizer st = new StringTokenizer(br.readLine());
	int n = Integer.parseInt(st.nextToken());
	int m = Integer.parseInt(st.nextToken());
	int k = Integer.parseInt(st.nextToken());

	int leafCnt = 1;
	while (leafCnt < n)
		leafCnt *= 2;
	long[] indexedTree = new long[leafCnt * 2];

	for (int i = 0; i < n; i++) {
		indexedTree[leafCnt + i] = Integer.parseInt(br.readLine());
	}

	initializeTree(indexedTree, leafCnt);

	for (int i = 0; i < m + k; i++) {
		st = new StringTokenizer(br.readLine());
		int type = Integer.parseInt(st.nextToken());
		int b = Integer.parseInt(st.nextToken());
		int c = Integer.parseInt(st.nextToken());

		if (type == 1) {
			updateTree(indexedTree, leafCnt + b - 1, c);
		} else {
			bw.write(query(indexedTree, leafCnt + b - 1, leafCnt + c - 1) + "\n");
		}
	}

	bw.flush();
	bw.close();
	br.close();
}

private static void initializeTree(long[] tree, int leafStart) {
	for (int i = leafStart - 1; i > 0; i--) {
		tree[i] = (tree[i * 2] * tree[i * 2 + 1]) % MOD;
	}
}

private static void updateTree(long[] tree, int idx, int val) {
	tree[idx] = val;
	while (idx > 1) {
		idx /= 2;
		tree[idx] = (tree[idx * 2] * tree[idx * 2 + 1]) % MOD;
	}
}

private static long query(long[] tree, int start, int end) {
	long result = 1;
	while (start <= end) {
		if (start % 2 == 1)
			result = (result * tree[start++]) % MOD;
		if (end % 2 == 0)
			result = (result * tree[end--]) % MOD;
		start /= 2;
		end /= 2;
	}
	return result;
}

출처:https://www.acmicpc.net/problem/11505