线段树区间查询

  1 #include <cstdio>
  2 #include <cstdlib>
  3 #include <cmath>
  4 #include <cstring>
  5 #include <time.h>
  6 #include <string>
  7 #include <set>
  8 #include <map>
  9 #include <list>
 10 #include <stack>
 11 #include <queue>
 12 #include <vector>
 13 #include <bitset>
 14 #include <ext/rope>
 15 #include <algorithm>
 16 #include <iostream>
 17 using namespace std;
 18 #define ll long long
 19 #define minv 1e-6
 20 #define inf 1e9
 21 #define pi 3.1415926536
 22 #define E  2.7182818284
 23 const ll mod=1e9+7;//998244353
 24 const int maxn=1e5+10;
 25 
 26 int tag[maxn<<2],sum[maxn<<2];
 27 
 28 void push_down(int index,int len)
 29 {
 30     tag[index<<1]=tag[index<<1|1]=tag[index];
 31     sum[index<<1]=((len+1)>>1)*tag[index];
 32     sum[index<<1|1]=(len>>1)*tag[index];
 33     tag[index]=0;
 34 }
 35 
 36 void build(int index,int l,int r)
 37 {
 38     tag[index]=0;
 39     if (l==r)
 40         sum[index]=1;
 41     else
 42     {
 43         int m=(l+r)>>1;
 44         build(index<<1,l,m);
 45         build(index<<1|1,m+1,r);
 46         sum[index]=sum[index<<1]+sum[index<<1|1];
 47     }
 48 }
 49 
 50 void update(int index,int l,int r,int s,int t,int v)
 51 {
 52     if (s<=l && r<=t)
 53     {
 54         tag[index]=v;
 55         sum[index]=(r-l+1)*v;
 56         return;
 57     }
 58     if (tag[index]!=0)
 59         push_down(index,r-l+1);
 60     int m=(l+r)>>1;
 61     if (s<=m)
 62         update(index<<1,l,m,s,t,v);
 63     if (m<t)
 64         update(index<<1|1,m+1,r,s,t,v);
 65     sum[index]=sum[index<<1]+sum[index<<1|1];
 66 }
 67 
 68 int query(int index,int l,int r,int s,int t)
 69 {
 70     if (s<=l && r<=t)
 71         return sum[index];
 72     if (tag[index]!=0)
 73         push_down(index,r-l+1);
 74     if (r<s || l>t)
 75         return 0;
 76     else
 77     {
 78         int m=(l+r)>>1;
 79         return query(index<<1,l,m,s,t)+query(index<<1|1,m+1,r,s,t);
 80     }
 81 }
 82 
 83 int main()
 84 {
 85     int t,T,n,q,x,y,v;
 86     scanf("%d",&t);
 87     for (T=1;T<=t;T++)
 88     {
 89         scanf("%d",&n);
 90         build(1,1,n);
 91         scanf("%d",&q);
 92         while (q--)
 93         {
 94             scanf("%d%d%d",&x,&y,&v);
 95             update(1,1,n,x,y,v);
 96         }
 97         printf("Case %d: The total value of the hook is %d.\n",T,query(1,1,n,1,n));
 98     }
 99     return 0;
100 }