51Nod 1174区间中最大的数

题目链接：https://www.51nod.com/onlineJudge/questionCode.html#!problemId=1174

import java.util.Scanner;public class Main{static int N = 10000;static TNode[] q = new TNode[N*4];static int[] a = new int[N];public static void main(String[] args) {Scanner scanner = new Scanner(System.in);int n = scanner.nextInt();for(int i = 0; i < n; i++) {a[i] = scanner.nextInt();}build(0, 0, n-1);//查询的个数int m = scanner.nextInt();for(int i = 0; i < m; i++) {int left = scanner.nextInt();int right = scanner.nextInt();int tmp = query(0,0,n-1, left, right);System.out.println(tmp);}}public static void build(int i,int left,int right) {q[i] = new TNode();q[i].mark = 0;if (left == right) {q[i].val = a[left];} else {int mid = (left + right) / 2;build(i*2+1, left, mid);build(i*2+2, mid+1, right);q[i].val = Math.max(q[i*2+1].val, q[i*2+2].val);}}public static void pushDown(int i) {if(q[i].mark != 0) {q[i*2+1].mark += q[i].mark;q[i*2+2].mark += q[i].mark;q[i*2+1].val += q[i].mark;q[i*2+2].val += q[i].mark;q[i].mark = 0;}}public static int query(int i,int nstart,int nend,int left,int right) {if(nend < left || right < nstart) {return -1;}//当前节点区间包含在查询区间内if(left <= nstart && right >= nend) {return q[i].val;}pushDown(i);int mid = (nstart + nend) / 2;return Math.max(query(i*2+1,nstart,mid, left, right), query(i*2+2,mid+1,nend, left, right));}}class TNode {int mark;int val;}