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.
题意很好理解,就是标准的线段树区间更新问题,可以说是模板。
不过因为写的不熟练,被坑了两个WA,错的地方在代码里标出来了。。。
代码如下:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include<iostream> #include<cstdio> #define lson L,M,po*2 #define rson M+1,R,po*2+1 using namespace std; long long BIT[100005*4]; long long COL[100005*4]; void pushUP(int po) { BIT[po]=BIT[po*2]+BIT[po*2+1]; } void pushDown(int po,int len) { if(COL[po]) { BIT[po*2]+=(long long)COL[po]*(len-(len/2)); BIT[po*2+1]+=(long long)COL[po]*(len/2); COL[po*2]+=COL[po]; //注意是+=,不是= !!! COL[po*2+1]+=COL[po]; COL[po]=0; } } void build_tree(int L,int R,int po) { if(L==R) { COL[po]=0; cin>>BIT[po]; return; } int M=(L+R)/2; build_tree(lson); build_tree(rson); pushUP(po); } long long query(int ql,int qr,int L,int R,int po) { if(ql<=L&&qr>=R) return BIT[po]; pushDown(po,(R-L+1)); int M=(L+R)/2; if(qr<=M) return query(ql,qr,lson); if(ql>M) return query(ql,qr,rson); return query(ql,qr,rson)+query(ql,qr,lson); } void update(int ul,int ur,int add,int L,int R,int po) { if(ul<=L&&ur>=R) { BIT[po]+=(long long)add*(R-L+1); COL[po]+=(long long)add; return; } pushDown(po,R-L+1); int M=(L+R)/2; if(ul<=M) update(ul,ur,add,lson); if(ur>M) update(ul,ur,add,rson); pushUP(po); } int main() { int N,Q; char C; int a,b,c; while(~scanf("%d %d",&N,&Q)) { build_tree(1,N,1); for(int i=0;i<Q;++i) { cin>>C; if(C=='Q') { scanf("%d %d",&a,&b); cout<<query(a,b,1,N,1)<<endl; } else { scanf("%d %d %d",&a,&b,&c); update(a,b,c,1,N,1); } } } return 0; }