线段树，懒惰标记
1 #include <cstdio> 2 #include <iostream> 3 using namespace std; 4 #define N 400010 5 int sum[N],lazy[N]; 6 void pushup(int root){ 7 sum[root]=sum[root*2]+sum[root*2+1]; 8 } 9 void pushdown(int root,int x){ 10 if(lazy[root] != -1) { 11 lazy[root*2] = lazy[root*2+1] = lazy[root]; 12 sum[root*2]=(x-x/2)*lazy[root]; 13 sum[root*2+1]=x/2*lazy[root]; 14 lazy[root]=-1; 15 } 16 } 17 void build(int l,int r,int root){ 18 lazy[root]=-1,sum[root]=1; 19 if(l==r)return ; 20 int mid=(l+r)/2; 21 build(l,mid,root*2); 22 build(mid+1,r,root*2+1); 23 pushup(root); 24 } 25 26 void query(int x,int y,int l,int r,int root,int a){ 27 if(x<=l&&y>=r){ 28 lazy[root] = a; 29 sum[root] = a*(r-l+1); 30 return; 31 } 32 pushdown(root,r-l+1); 33 int mid=(r+l)/2; 34 if(x<=mid)query(x,y,l,mid,root*2,a); 35 if(y>mid)query(x,y,mid+1,r,root*2+1,a); 36 pushup(root); 37 } 38 int main(){ 39 //freopen("test.txt","r",stdin); 40 int t,n,q,x,y,z,case1=0; 41 scanf("%d",&t); 42 while(t--){ 43 case1++; 44 scanf("%d%d",&n,&q); 45 build(1,n,1); 46 for(int i=0;i<q;i++){ 47 scanf("%d%d%d",&x,&y,&z); 48 query(x,y,1,n,1,z); 49 } 50 printf("Case %d: The total value of the hook is %d. ",case1,sum[1]); 51 } 52 return 0; 53 }