HDU 之 I Hate It

#include <stdio.h>
#include <string.h>

struct N
{
    int w;
}q[550000];

int max(int a, int b)
{
    return a>b?a:b;
}

void build(int x, int k, int left, int right, int rt )
{
    if(x<left || x>right )
    {
        return ;
    }
    if(x==left && x==right )
    {
        q[rt].w = k;
        return;
    }
    build(x, k, left, (left+right)/2, rt*2 );
    build(x, k, (left+right)/2+1, right, rt*2+1 );
    q[rt].w = max( q[rt*2].w, q[rt*2+1].w ) ;
}

int query(int ll, int rr, int left, int right, int rt )
{
    if(rr<left || ll>right )
    {
        return 0;
    }
    if(ll<=left && rr>=right )
    {
        return q[rt].w;
    }
    return max(query(ll, rr, left, (left+right)/2, rt*2),query(ll, rr,
                                                            (left+right)/2+1,right, rt*2+1 ));
}


int main()
{
    int n, m;
    int i, j;
    char ch;
    int ss, dd;
    int A; int B;
    while(scanf("%d %d", &n, &m)!=EOF)
    {
        for(i=1; i<=n; i++)
        {
            scanf("%d%*c", &dd); //cha ru
            build(i,dd, 1, n, 1);
        }
        for(j=0; j<m; j++)
        {
            scanf("%c %d %d%*c", &ch, &A, &B);

            if(ch==‘Q‘)
            {
                ss = query(A, B, 1, n, 1) ;
                printf("%d\n", ss );
            }
            else if(ch==‘U‘)
            {
                build(A, B, 1, n, 1);
            }

        }
    }
    return 0;
}

#include <cstdio>
#include <cmath>
#include <iostream>
using namespace std;

const int MAXNODE = 524288; // 1<<19
const int MAXST = 200001;
struct STU{
	int grade;
	int left,right;
}st[MAXNODE];

int father[MAXST];

void BuildTree(int i,int left,int right){ // i是结点的序号 对应了数组下标
	st[i].left = left;
	st[i].right = right;
	st[i].grade = 0; // 初始化为0
	if (left == right)
	{
		father[left] = i; // 为了更新的时候从下往上 一直到顶
		return;
	}
	BuildTree(i*2, left, (int)floor( (right+left) / 2.0));
	BuildTree(i*2+1, (int)floor( (right+left) / 2.0) + 1, right);
}

void UpdataTree(int ri)// 从下往上更新
{	
	if (ri == 1)
	{
		return;
	}
	int fi = ri / 2; // 父结点
	int a = st[fi<<1].grade; // 该父结点的两个子结点
	int b = st[(fi<<1)+1].grade;

	st[fi].grade = (a > b)?(a):(b);
	UpdataTree(ri/2);
	
}

int Max;
void Query(int i,int l,int r){ // i为区间的序号，四段查询 即四种情况
	
	if (st[i].left == l && st[i].right == r)  // 找到了一个完全重合的区间
	{
		Max = (Max < st[i].grade)?st[i].grade:(Max);
		return ;
	}
	i = i << 1; // left child of the tree
	if (l <= st[i].right) // 左区间有覆盖
	{
		if (r <= st[i].right) // 全包含于左区间
		{
			Query(i, l, r);
		}
		else // 半包含于左区间
		{
			Query(i, l, st[i].right);
		}
	}
	i += 1; // right child of the tree
	if (r >= st[i].left) // 右区间有覆盖
	{
		if (l >= st[i].left) // 全包含于右区间
			Query(i, l, r);
		else // 半包含于左区间
			Query(i, st[i].left, r);
	}
}

int main()
{
	int n_s,n_q,igrade; 
	
	while(scanf("%d %d",&n_s,&n_q) != EOF){
		BuildTree(1, 1, n_s); 
		for (int i= 1 ; i <= n_s; i++)
		{
			scanf("%d", &igrade );

			st[father[i]].grade = igrade; // 底层的无条件更新成绩

			UpdataTree(father[i]);
		}
		while(n_q--)
		{
			char o[3];int a,b;

			scanf("%s %d %d",o,&a,&b);

			if ( o[0] == ‘Q‘)
			{
				Max = 0;
				Query(1, a, b);
				printf("%d\n",Max);
			}
			else
			{
				st[father[a]].grade = b; // 底层的无条件更新成绩
				UpdataTree(father[a]);
			}
		}
	}
	return 0;
}