poj 2528 Mayor's posters 离散化 线段树

#include<iostream>#include<algorithm>#include<vector>using namespace std;struct gg{int x; int id;gg(){}gg(int xx,int idd){x=xx; id=idd;}};bool cmp(gg a,gg b){return a.x<b.x;}int main(){freopen("in.txt","r",stdin);int test;cin>>test;while(test--){int n; cin>>n; //int cnt=1;int cnt=1;vector<gg> vec;for(int i=1;i<=n;i++){int a,b;scanf("%d%d",&a,&b);vec.push_back(gg(a,i));vec.push_back(gg(b+1,i));}sort(vec.begin(),vec.end(),cmp);for(int i=0;i<vec.size();i++){if(i+1<vec.size() && vec[i].x!=vec[i+1].x) vec[i].x = cnt++;else vec[i].x = cnt;}int start[10000*3]; int end[10000*3];memset(start,0,sizeof(start));memset(end,0,sizeof(end));for(int i=0;i<vec.size();i++){if(start[vec[i].id]==0)start[vec[i].id]=vec[i].x;elseend[vec[i].id]=vec[i].x;}int flag[10000*3]; bool flag2[10000*3];memset(flag,0,sizeof(flag));memset(flag2,0,sizeof(flag2));for(int i=1;i<=n;i++)for(int j=start[i];j<end[i];j++)flag[j]=i;for(int i=1;i<=cnt;i++)flag2[flag[i]]=1;int ans=0;for(int i=1;i<=n;i++)if(flag2[i]) ans++;cout<<ans<<endl;}}

#include<iostream>#include<vector>#include<algorithm>using namespace std;const int maxn=10005;bool flag[maxn*5];struct gg{int x; int id;gg(){}gg(int xx,int idd){x=xx; id=idd;}};bool cmp(gg a,gg b){return a.x<b.x;}struct seg_tree{int left; int right; int val;int calmid(){return (left+right)>>1;}};seg_tree tt[100000*2*3];void build(int left,int right,int idx){tt[idx].left=left; tt[idx].right=right;tt[idx].val = 0;if(left == right) return;int mid = tt[idx].calmid();build(left,mid,idx<<1);build(mid+1,right,idx<<1|1);}void inherit(int idx){if(tt[idx].val){tt[idx<<1].val=tt[idx<<1|1].val=tt[idx].val;tt[idx].val=0;}}void update(int left,int right,int v,int idx){if(left == tt[idx].left && right == tt[idx].right){tt[idx].val = v;return;}inherit(idx);int mid = tt[idx].calmid();if(right<=mid) update(left,right,v,idx<<1);else if(left>mid) update(left,right,v,idx<<1|1);else {update(left,mid,v,idx<<1);update(mid+1,right,v,idx<<1|1);}}void query(int left,int right,int idx){if(left == tt[idx].left && right == tt[idx].right && tt[idx].val){flag[tt[idx].val]=1;return;}inherit(idx);int mid = tt[idx].calmid();if(right <= mid) query(left,right,idx<<1);else if(left>mid) query(left,right,idx<<1|1);else {query(left,mid,idx<<1);query(mid+1,right,idx<<1|1);}}int main(){freopen("in.txt","r",stdin);int test; cin>>test;while(test--){int n;vector<gg> vec;cin>>n;for(int i=1;i<=n;i++){int a,b;scanf("%d%d",&a,&b);vec.push_back(gg(a,i));vec.push_back(gg(b,i));}sort(vec.begin(),vec.end(),cmp);int cnt=1;for(int i=0;i<vec.size();i++){if(i+1<vec.size() && vec[i].x!=vec[i+1].x){ vec[i].x=cnt++;}else vec[i].x=cnt;}int st[maxn]; int end[maxn];memset(st,-1,sizeof(st));memset(end,0,sizeof(end));for(int i=0;i<vec.size();i++){if(st[vec[i].id]==-1) st[vec[i].id]=i;else end[vec[i].id]=i;}build(1,cnt,1);for(int i=1;i<=n;i++){update(vec[st[i]].x,vec[end[i]].x,i,1);}memset(flag,0,sizeof(flag));query(1,cnt,1);int ans=0;for(int i=1;i<=n;i++)if(flag[i]) ans++;cout<<ans<<endl;}}