ACM基础训练题解4301 城市地平线
遍历线段树 线段树的插入和查询
1 //城市地平线(线段树) 2 #include<iostream> 3 #include<cstdlib> 4 #include<cstring> 5 #include<algorithm> 6 #include<cstdio> 7 using namespace std; 8 typedef __int64 LL; 9 struct building{ 10 LL x1; 11 LL x2; 12 LL height; 13 }line[50000]; 14 LL node[100000]; 15 struct tree{ 16 LL left; 17 LL right; 18 LL hi; 19 }treenode[1000000]; 20 bool cmp(building a,building b){ 21 return (a.height<b.height ); 22 } 23 void clear(int n){ 24 memset(treenode,0,sizeof(treenode)); 25 memset(node,0,sizeof(node)); 26 memset(line,0,sizeof(line)); 27 for(int i=1;i<=n;i++){ 28 cin>>line[i].x1>>line[i].x2>>line[i].height; 29 node[i*2-1]=line[i].x1; 30 node[i*2]=line[i].x2; 31 } 32 sort(line+1,line+n+1,cmp); 33 int j=1; 34 sort(node+1,node+1+2*n); 35 for(int i=1;i<=n*2;i++){ 36 if(node[j]!=node[i]) 37 node[++j]=node[i]; 38 } 39 node[0]=j; 40 return ; 41 } 42 void creatree(int ll,int rr,int p){ 43 treenode[p].left=node[ll]; 44 treenode[p].right=node[rr]; 45 if(ll+1==rr) 46 return ; 47 int mid=(ll+rr)/2; 48 creatree(ll,mid,p*2); 49 creatree(mid,rr,p*2+1);//*** 50 return ; 51 } 52 void insert(LL ileft,LL iright,LL value,int p){ 53 if(ileft<=treenode[p].left && treenode[p].right<=iright){ 54 treenode[p].hi=value; 55 return ; 56 } 57 if(treenode[p].hi>0) 58 treenode[p*2].hi=treenode[p*2+1].hi=treenode[p].hi; 59 treenode[p].hi=-1; 60 if(iright>treenode[p*2].right) 61 insert(ileft,iright,value,p*2+1); 62 if(ileft<treenode[p*2].right) 63 insert(ileft,iright,value,p*2); 64 return ; 65 } 66 LL search(int p){ 67 if(treenode[p].hi>0) 68 return (treenode[p].hi*(treenode[p].right-treenode[p].left)); 69 if(treenode[p].hi==0) 70 return 0; 71 return (search(p*2)+search(p*2+1)); 72 } 73 int main(){ 74 int n; 75 cin>>n; 76 clear(n); 77 creatree(1,node[0],1); 78 for(int i=1;i<=n;i++) 79 insert(line[i].x1,line[i].x2,line[i].height,1); 80 cout<<search(1)<<endl; 81 return 0; 82 }
