【算法系列学习】线段树 区间修改，区间求和 [kuangbin带你飞]专题七 线段树 C - A Simple Problem with Integers

https://vjudge.net/contest/66989#problem/C

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<string>
 #include<algorithm>
 #include<cmath>
 #define lson (i<<1)
 #define rson (i<<1|1)
 typedef long long ll;
 using namespace std;
 const int maxn=1e5+;
 ll val[maxn];

 struct Seg
 {
     int l,r;
     ll lazy,val;
 }tree[maxn<<];

 void push_up(int i)
 {
     tree[i].val=tree[lson].val+tree[rson].val;
 }

 void push_down(int i)
 {
     if(tree[i].lazy==)
     {
         return;
     }
     tree[lson].lazy+=tree[i].lazy;
     tree[lson].val+=tree[i].lazy*(tree[lson].r-tree[lson].l+);
     tree[rson].lazy+=tree[i].lazy;
     tree[rson].val+=tree[i].lazy*(tree[rson].r-tree[rson].l+);
     tree[i].lazy=;
 }

 void Build(int l,int r,int i=)
 {
     tree[i].l=l;
     tree[i].r=r;
     tree[i].lazy=;
     if(l==r)
     {
         tree[i].val=val[l];
         return;
     }
 //    push_down(i);
     int mid=(tree[i].l+tree[i].r)>>;
     Build(l,mid,lson);
     Build(mid+,r,rson);
     push_up(i);
 }

 ll Query(int l,int r,int i=)
 {
     if(tree[i].l==l&&tree[i].r==r)
     {
         return tree[i].val;
     }
     push_down(i);
     int mid=(tree[i].l+tree[i].r)>>;
     if(r<=mid)
     {
         return Query(l,r,lson);
     }
     else if(l>mid)
     {
         return Query(l,r,rson);
     }
     else
     {
         return Query(l,mid,lson)+Query(mid+,r,rson);
     }
 }

 void Add(int l,int r,ll x,int i=)
 {
     if(tree[i].l==l&&tree[i].r==r)
     {
         tree[i].lazy+=x;
         tree[i].val+=x*(ll)(r-l+);
         return;
     }
     push_down(i);
     int mid=(tree[i].l+tree[i].r)>>;
     if(r<=mid)
     {
         Add(l,r,x,lson);
     }
     else if(l>mid)
     {
         Add(l,r,x,rson);
     }
     else
     {
         Add(l,mid,x,lson);
         Add(mid+,r,x,rson);
     }
     push_up(i);
  } 

 int main()
 {
     int n,m;
     while(~scanf("%d%d",&n,&m))
     {
         for(int i=;i<=n;i++)
         {
             scanf("%lld",&val[i]);
         }
         Build(,n);
         char q[];
         int a,b,c;
         for(int i=;i<=m;i++)
         {
             scanf("%s%d%d",q,&a,&b);
             if(q[]=='Q')
             {
                 printf("%lld\n",Query(a,b));
             }
             else
             {
                 scanf("%d",&c);
                 Add(a,b,c);
             }
         }
     }
     return ;
  }