poj 2828 Buy Tickets【线段树 单点更新】

倒着插，先不理解意思，后来看一篇题解说模拟一下

手动模拟一下就好理解了-----

不过话说一直写挫---一直改啊-----

好心塞------

 #include <cstdio>
 #include <ctime>
 #include <cstring>
 #include <cstdlib>
 #include <cmath>
 #include <vector>
 #include <map>
 #include <set>
 #include <stack>
 #include <queue>
 #include <string>
 #include <iostream>
 #include <algorithm>
 using namespace std;

 #define getmid(l,r) ((l) + ((r) - (l)) / 2)

 typedef long long LL;
 const double eps = 1e-;
 const int INF = ( << ) - ;
 const int maxn = ;

 struct node{
     int l,r,s;
 }t[*maxn];

 struct Edge{
     int pos,val;
 }a[maxn];

 int n;
 int ans[maxn];

 void Push_up(int p){
     t[p].s = t[p<<].s + t[p<<|].s;
 }

 void Build_tree(int p,int l,int r){
     t[p].l = l;
     t[p].r = r;
     if(l == r){
         t[p].s = ;
         return;
     }
     int mid = getmid(l,r);
     Build_tree(p<<,l,mid);
     Build_tree(p<<|,mid+,r);
     Push_up(p);
 }

 void update(int idx,int p){
     if(t[p].l == t[p].r){
         t[p].s--;
         return;
     }
     int mid = getmid(t[p].l,t[p].r);
     if(idx <= mid) update(idx,p<<);
     else update(idx,p<<|);
     Push_up(p);
 }

 int query(int idx,int p){
     if(t[p].l == t[p].r) return t[p].l;
     if(t[p<<].s >= idx) return query(idx,p<<);
     else return query(idx-t[p<<].s,p<<|);
 }

 void solve(){
     Build_tree(,,n);
 //    for(int i = 1;i <= 2*n;i++)
 //    printf("t[%d].l = %d  t[%d].r = %d  t[%d].s = %d\n",i,t[i].l,i,t[i].r,i,t[i].s);
     for(int i = n;i >= ;i--){
         int pos = a[i].pos;
         int id = query(pos,);
         ans[id] = a[i].val;
         update(id,);
     }
     printf("%d",ans[]);
     for(int i = ;i <= n;i++) printf(" %d",ans[i]);
     printf("\n");
 }

 int main(){
     while(scanf("%d",&n) != EOF){
         for(int i = ;i <= n;i++){
             scanf("%d %d",&a[i].pos,&a[i].val);
             a[i].pos++;
         }
         solve();
     }
     return ;
 }

加油啊~~~~