HDU1698 Just a Hook

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<cstring>
 5 #include<cmath>
 6 #define ls l,mid,rt<<1
 7 #define rs mid+1,r,rt<<1|1
 8 using namespace std;
 9 const int mxn=200000;
10 int n,m;
11 int ans=0;
12 struct tree{
13     int sum;
14     int add;
15 }tr[mxn*4];
16 void Build(int l,int r,int rt){
17     if(l==r){
18         tr[rt].sum=1;
19         tr[rt].add=0;
20         return;
21     }
22     int mid=(l+r)>>1;
23     Build(ls);
24     Build(rs);
25     tr[rt].sum=tr[rt<<1].sum+tr[rt<<1|1].sum;
26     return;
27 }
28 void change(int L,int R,int x,int l,int r,int rt){
29     if(tr[rt].add){
30         int mid=(l+r)>>1;
31         tr[rt<<1].sum=(mid-l+1)*tr[rt].add;//更新下面的值很重要！ 
32         tr[rt<<1|1].sum=(r-mid)*tr[rt].add;//更新！ 
33         tr[rt<<1].add=tr[rt<<1|1].add=tr[rt].add;
34         tr[rt].add=0;
35     }
36     if(L<=l && r<=R){    
37         tr[rt].sum=(r-l+1)*x;
38         tr[rt].add=x;
39         return;
40     }
41     int mid=(l+r)>>1;
42     if(L<=mid)change(L,R,x,ls);
43     if(R>mid)change(L,R,x,rs);
44     tr[rt].sum=tr[rt<<1].sum+tr[rt<<1|1].sum;
45     return;
46 }
47 
48 int main(){
49     int T;
50     scanf("%d",&T);
51     for(int ro=1;ro<=T;ro++){
52         memset(tr,0,sizeof tr);
53         scanf("%d",&n);
54         Build(1,n,1);
55         scanf("%d",&m);
56         int i,j;
57         int x,y,z;
58         for(i=1;i<=m;i++){
59             scanf("%d%d%d",&x,&y,&z);
60             change(x,y,z,1,n,1);
61         }
62         printf("Case %d: The total value of the hook is %d.\n",ro,tr[1].sum);
63         
64     }
65     return 0;
66 }