标签：des style blog http color os strong io
| Time Limit: 5000MS | Memory Limit: 131072K | |
| Total Submissions: 59798 | Accepted: 18237 | |
| Case Time Limit: 2000MS | ||
Description
You have N integers, A1, A2, ... , AN. You need to deal with two kinds of operations. One type of operation is to add some given number to each number in a given interval. The other is to ask for the sum of numbers in a given interval.
Input
The first line contains two numbers N and Q. 1 ≤ N,Q ≤ 100000.
The second line contains N numbers, the initial values of A1, A2, ... , AN. -1000000000 ≤ Ai ≤ 1000000000.
Each of the next Q lines represents an operation.
"C a b c" means adding c to each of Aa, Aa+1, ... , Ab. -10000 ≤ c ≤ 10000.
"Q a b" means querying the sum of Aa, Aa+1, ... , Ab.
Output
You need to answer all Q commands in order. One answer in a line.
Sample Input
10 5 1 2 3 4 5 6 7 8 9 10 Q 4 4 Q 1 10 Q 2 4 C 3 6 3 Q 2 4
Sample Output
4 55 9 15
Hint
Source
【题目大意】
一个数列，每次操作可以是将某区间数字都加上一个相同的整数，也可以是询问一个区间中所有数字的和。（这里区间指的是数列中连续的若干个数）对每次询问给出结果。
【题目分析】
裸的区间更新线段树。
线段树单点更新和区间更新的区别：
1.每个结点中多了一个add值，代表该结点以下的结点需要增加的值；
2.build函数中，如果在建树的过程中就赋值给num，那么在建完树之后不要忘记pushup,因为此时只是叶子结点有值，上面的值都为空；这个在区间更新中很常用，因为区间更新中如果输入一个值，然后更新一个值，这样会很麻烦，会耗费更多的时间；
3.update函数中，区间更新多了一个upshdown函数，并且更新sum和add值的判断条件是树中结点的l~r和要更新的区间的l~r相等，此时sum加的值是整个区间的长度*要更新的值，然后add值记录后面每个结点需要加上的值，即：c;
4.upshdown函数最后不要忘了将延时标记add清零；
//Memory Time
// K MS
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<vector>
#include<queue>
#include<stack>
#include<iomanip>
#include<string>
#include<climits>
#include<cmath>
#define MAX 110000
#define LL long long
using namespace std;
LL n,m;
LL ans;
struct Tree
{
LL l,r;
LL sum,add;
};
Tree tree[MAX*3];
void pushup(LL x)
{
LL tmp=2*x;
tree[x].sum=tree[tmp].sum+tree[tmp+1].sum;
}
void pushdown(LL x)
{
LL tmp=2*x;
tree[tmp].add+=tree[x].add;
tree[tmp+1].add+=tree[x].add;
tree[tmp].sum+=tree[x].add*(tree[tmp].r-tree[tmp].l+1);
tree[tmp+1].sum+=tree[x].add*(tree[tmp+1].r-tree[tmp+1].l+1);
tree[x].add=0;
}
void build(int l,int r,int x)
{
tree[x].l=l;
tree[x].r=r;
tree[x].add=0;
if(l==r)
{
scanf("%lld",&tree[x].sum);
return ;
}
int tmp=x<<1;
int mid=(l+r)>>1;
build(l,mid,tmp);
build(mid+1,r,tmp+1);
pushup(x); //如果在建树的过程中给sum赋值，记得后面要pushup
}
void update(LL l,LL r,LL c,LL x)
{
if(r<tree[x].l||l>tree[x].r)
return ;
if(l<=tree[x].l&&r>=tree[x].r)
{
tree[x].add+=c;
tree[x].sum+=c*(tree[x].r-tree[x].l+1);
return ;
}
if(tree[x].add)
pushdown(x);
LL tmp=x<<1;
update(l,r,c,tmp); // !!!
update(l,r,c,tmp+1);
pushup(x);
}
void query(LL l,LL r,LL x)
{
if(r<tree[x].l||l>tree[x].r) //要更新的区间不在该区间上
return ;
if(l<=tree[x].l&&r>=tree[x].r) //要更新区间包括了该区间
{
ans+=tree[x].sum;
return ;
}
if(tree[x].add)
pushdown(x);
LL tmp=x<<1;
LL mid=(tree[x].l+tree[x].r)>>1;
if(r<=mid)
query(l,r,tmp);
else if(l>mid)
query(l,r,tmp+1);
else
{
query(l,mid,tmp);
query(mid+1,r,tmp+1);
}
// pushup(x);
}
int main()
{
// freopen("cin.txt","r",stdin);
// freopen("cout.txt","w",stdout);
while(~scanf("%lld %lld",&n,&m))
{
build(1,n,1);
char str[5];
while(m--)
{
scanf("%s",str);
if(str[0]==‘Q‘)
{
LL l,r;
scanf("%lld %lld",&l,&r);
ans=0;
query(l,r,1);
printf("%lld\n",ans);
}
else
{
LL l,r,c;
scanf("%lld %lld %lld",&l,&r,&c);
update(l,r,c,1);
}
}
}
return 0;
}
线段树 + 区间更新 + 模板 ---- poj 3468,布布扣,bubuko.com
标签：des style blog http color os strong io
原文地址：http://www.cnblogs.com/acmer-jsb/p/3879043.html
