线段树入门题

//hdu1754
#include<stdio.h>
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1 //注意因为这里右边是+1的，所以在下面更新以及查询时要注意是否要加=号！！！
#define maxn 200020
int sum[maxn<<2],a[maxn];
int max(int x,int y)
{
	return x>y?x:y;
}
void PushUP(int rt)
{
	sum[rt] = max(sum[rt<<1],sum[rt<<1|1]);
}
void build(int l,int r,int rt)//建树
{
	if(l == r)
	{
		sum[rt]=a[l];
		return;
	}
	int m = (l + r)>>1;
	build(lson);
	build(rson);
	PushUP(rt);
}
void Updata(int i,int B,int l,int r,int rt)//更新
{
	if(l == r)
	{
		sum[rt]=B;
		return ;
	}
	int m = (l + r)/2;
	if(m < i)
		Updata(i,B,rson);
	else Updata(i,B,lson);
	PushUP(rt);
}
int Query(int L,int R,int l,int r,int rt)//查询
{
	if(L <= l&&R >= r)
		return sum[rt];
	int m = (l + r)/2;
	int ret=-9999999;
	if(m < L)
		ret = max(ret,Query(L,R,rson));
	else if(m >= R)
		ret = max(ret,Query(L,R,lson));
	else
	{
		ret = max(ret,Query(L,R,lson));
		ret = max(ret,Query(L,R,rson));
	}
	return ret;
}
int main()
{
	int n,m,i;
	char s[3];
	while(scanf("%d%d",&n,&m)!=EOF)
	{

		for(i = 1; i <= n; i++)
			scanf("%d",&a[i]);
		build(1,n,1);
		int a,b;
		for(i = 0; i < m; i++)
		{
			scanf("%s",s);
			scanf("%d%d",&a,&b);
			if(s[0] == ‘U‘)
				Updata(a,b,1,n,1);
			else
				printf("%d\n",Query(a,b,1,n,1));
		}
	}
}

//hdu1166
#include<stdio.h>
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define maxn 50505
int sum[maxn<<2];
void PushUP(int rt)
{
	sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}
void build(int l,int r,int rt)
{
	if(l == r)
	{
		scanf("%d",&sum[rt]);
		return;
	}
	int m = (l + r)/2;
	build(lson);
	build(rson);
	PushUP(rt);
}
void Updata(int p,int add,int l,int r,int rt)
{
	if(l == r)
	{
		sum[rt] += add;
		return ;
	}
	int m = (l + r)/2;
	if(p <= m)
		Updata(p,add,lson);
	else 
		Updata(p,add,rson);
	PushUP(rt);
}
int Query(int L,int R,int l,int r,int rt)
{
	if(L <= l&&r <= R)
		return sum[rt];
	int ret = 0;
	int m = (l + r)/2;
	if(L > m)
		ret += Query(L,R,rson);
	else if(m >= R)
		ret += Query(L,R,lson);
	else
	{
		ret += Query(L,R,lson);
		ret += Query(L,R,rson);
	}
	return ret;
}
int main()
{
	int T , ff = 0 , n;
	scanf("%d",&T);
	while(T--)
	{
		printf("Case %d:\n",++ff);
		scanf("%d",&n);
		build(1,n,1);
		char s[10];
		while(scanf("%s",s)!=EOF)
		{
			if(s[0]==‘E‘)
				break;
			int a,b;
			scanf("%d%d",&a,&b);
			if(s[0]==‘A‘)
				Updata(a,b,1,n,1);
			else if(s[0]==‘S‘)
				Updata(a,-b,1,n,1);
			else if(s[0]==‘Q‘)
				printf("%d\n",Query(a,b,1,n,1));
		}
	}
}