2016夏季练习——线段树

来源：HDU1698

lazy标记的线段树

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#define lch (rt<<1)
#define rch (rt<<1|1)
using namespace std;
const int MAXN = 100000+10;
int tree[MAXN*4];
int lazy[MAXN*4];
int n;
int Q;
int x,y,v;
void pushup(int rt){
tree[rt]=tree[lch]+tree[rch];
return ;
}
void pushdown(int rt,int d){
//cout<<rt<<" "<<d<<endl;
if(lazy[rt]){
lazy[lch]=lazy[rt];
lazy[rch]=lazy[rt];
tree[lch]=lazy[rt]*(d-(d>>1));
tree[rch]=lazy[rt]*(d>>1);
lazy[rt]=0;
}
}
void build(int rt,int left,int right){
tree[rt]=1;
lazy[rt]=0;
if(left==right){
return ;
}
int mid=(left+right)>>1;
build(lch,left,mid);
build(rch,mid+1,right);
pushup(rt);
}
void update(int rt,int left,int right,int l,int r,int data){
if(left>=l&&r>=right){
lazy[rt]=data;
tree[rt]=(right-left+1)*data;
return ;
}
pushdown(rt,right-left+1);
int mid=(left+right)>>1;
if(l<=mid) update(lch,left,mid,l,r,data);
if(r>mid) update(rch,mid+1,right,l,r,data);
pushup(rt);
}
int main(){
int T,nc=1;
scanf("%d",&T);
while(T--){
scanf("%d",&n);
scanf("%d",&Q);
memset(tree,0,sizeof(tree));
memset(lazy,0,sizeof(lazy));
build(1,1,n);
for(int i=0;i<Q;i++){
scanf("%d%d%d",&x,&y,&v);
update(1,1,n,x,y,v);
//cout<<tree[1]<<endl;
}
cout<<"Case "<<nc++<<": The total value of the hook is "<<tree[1]<<"."<<endl;//注意最后一个句号
}
return 0;
}