题意：
区间修改，询问总和。
思路：
直接上线段树，裸题。
1 /* 2 * Author: windystreet 3 * Date : 2018-08-11 21:02:54 4 * Motto : Think twice, code once. 5 */ 6 #include<bits/stdc++.h> 7 8 using namespace std; 9 10 #define X first 11 #define Y second 12 #define eps 1e-5 13 #define gcd __gcd 14 #define pb push_back 15 #define PI acos(-1.0) 16 #define lowbit(x) (x)&(-x) 17 #define bug printf("!!!!! "); 18 #define mem(x,y) memset(x,y,sizeof(x)) 19 20 typedef long long LL; 21 typedef long double LD; 22 typedef pair<int,int> pii; 23 typedef unsigned long long uLL; 24 25 const int maxn = 1e5+7; 26 const int INF = 1<<30; 27 const int mod = 1e9+7; 28 29 struct Tree 30 { 31 int l,r,v,lazy; 32 }tree[maxn<<2]; 33 34 void build(int rt,int l,int r){ 35 tree[rt].lazy = 0;tree[rt].l=l,tree[rt].r=r; 36 if(l==r){ 37 tree[rt].v = 1;return; 38 } 39 int mid = (l+r)>>1; 40 build(rt<<1,l,mid); 41 build(rt<<1|1,mid+1,r); 42 tree[rt].v = tree[rt<<1].v + tree[rt<<1|1].v; 43 } 44 void pushup(int rt){ 45 tree[rt].v = tree[rt<<1].v+tree[rt<<1|1].v; 46 } 47 void pushdown(int rt){ 48 if(tree[rt].lazy){ 49 int mid = (tree[rt].l+tree[rt].r)>>1; 50 tree[rt<<1].lazy = tree[rt<<1|1].lazy = tree[rt].lazy; 51 tree[rt<<1].v = (mid - tree[rt].l + 1)*tree[rt].lazy; 52 tree[rt<<1|1].v = (tree[rt].r - mid )*tree[rt].lazy; 53 tree[rt].lazy = 0; 54 } 55 } 56 void update(int rt,int L, int R,int l, int r,int v){ 57 if(l<=L&&R<=r){ 58 tree[rt].lazy = v; 59 tree[rt].v = v*(R-L+1); 60 return; 61 } 62 pushdown(rt); // 每次修改之前先将标记下推 63 int mid = (L + R) >>1; 64 if(l<=mid) update(rt<<1,L,mid,l,r,v); 65 if(r>mid) update(rt<<1|1,mid+1,R,l,r,v); 66 pushup(rt); // 向上更新 67 } 68 69 70 void solve(){ 71 int n,m,x,y,v; 72 scanf("%d%d",&n,&m); 73 build(1,1,n); 74 while(m--){ 75 scanf("%d%d%d",&x,&y,&v); 76 update(1,1,n,x,y,v); 77 } 78 printf("%d. ",tree[1].v); 79 return; 80 } 81 82 int main() 83 { 84 // freopen("F:\in.txt","r",stdin); 85 // freopen("out.txt","w",stdout); 86 // ios::sync_with_stdio(false); 87 int t = 1,cas = 1; 88 scanf("%d",&t); 89 while(t--){ 90 printf("Case %d: The total value of the hook is ",cas++); 91 solve(); 92 } 93 return 0; 94 }