题意：
题解：
线段树模板题：区间add，区间sum。
这里没必要写query函数了，让求全体sum，所以这道题不用线段树也是可以滴~~~暴力呗。既然在线段树专题训练了，就老实线段树~！
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<queue>
#include<string>
#include<cstring>
#include<vector>
#include<functional>
#include<utility>
#include<set>
#include<map>
#include<cmath>
#include<cctype>
#define INF 0x3f3f3f3fusing namespace std;const int maxn=100000+10;
#define lson 2*i,l,m
#define rson 2*i+1,m+1,rint setv[maxn<<2],sum[maxn<<2];void pushup(int i)
{sum[i]=sum[2*i]+sum[2*i+1];
}void build(int i,int l,int r)
{setv[i]=0;if(l==r){sum[i]=1;return;}int m=(l+r)/2;build(lson);build(rson);pushup(i);
}void pushdown(int i,int num)
{if(setv[i]){setv[2*i]=setv[2*i+1]=setv[i];sum[2*i+1]=(num/2)*setv[i];sum[2*i]=(num-num/2)*setv[i];setv[i]=0;}
}
void update(int ql, int qr, int v, int i, int l, int r)
{if(ql<=l&&qr>=r){setv[i]=v;sum[i]=v*(r-l+1);return;}pushdown(i,r-l+1);int m=(l+r)/2;if(ql<=m)update(ql,qr,v,lson);if(qr>m)update(ql,qr,v,rson);pushup(i);
}int query(int ql,int qr,int i,int l,int r)
{if(ql<=l&&qr>=r){return sum[i];}pushdown(i,r-l+1);int m=(l+r)/2;int res=0;if(ql<=m)res+=query(ql,qr,lson);if(qr<m)res+=query(ql,qr,rson);return res;
}int main()
{int t;cin>>t;for(int kase=1;kase<=t;kase++){int n,q;cin>>n>>q;build(1,1,n);while(q--){int x,y,z;scanf("%d%d%d",&x,&y,&z);update(x,y,z,1,1,n);}printf("Case %d: The total value of the hook is %d.\n",kase,sum[1]);//无需query}}