[hdu5372 Segment Game]树状数组

题意：有两种操作：(1)插入线段，第i次插入的线段左边界为Li，长度为i (2)删除线段，删除第x次插入的线段。每次插入线段之前询问有多少条线段被它覆盖。

思路：由于插入的线段长度是递增的，所以第i次插入的线段的长度比以前插入的所有线段都要长，从以前插入的线段里面任取一条，考虑其与当前线段的位置关系，主要有以下三种：

图中，下方表示当前线段。注意到，只有被当前线段覆盖的线段，它的左右边界和当前线段的左右边界的相对位置是不同的。也就是说，查询有多少个线段的右端点小于等于该线段右端点，再查询有多少条线段左端点小于该线段的左端点，两者之差就是答案。因为不符合要求的线段同时进入了前者和后者，而符合要求的答案只进入了前者。

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//#pragma comment(linker, "/STACK:1024000000")
#include <map>
#include <set>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <vector>
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>using namespace std;#define X                   first
#define Y                   second
#define pb                  push_back
#define mp                  make_pair
#define all(a)              (a).begin(), (a).end()
#define fillchar(a, x)      memset(a, x, sizeof(a))
#define copy(a, b)          memcpy(a, b, sizeof(a))typedef long long ll;
typedef pair<int, int> pii;
typedef unsigned long long ull;//#ifndef ONLINE_JUDGE
void RI(vector<int>&a,int n){a.resize(n);for(int i=0;i<n;i++)scanf("%d",&a[i]);}
void RI(){}void RI(int&X){scanf("%d",&X);}template<typename...R>
void RI(int&f,R&...r){RI(f);RI(r...);}void RI(int*p,int*q){int d=p<q?1:-1;
while(p!=q){scanf("%d",p);p+=d;}}void print(){cout<<endl;}template<typename T>
void print(const T t){cout<<t<<endl;}template<typename F,typename...R>
void print(const F f,const R...r){cout<<f<<", ";print(r...);}template<typename T>
void print(T*p, T*q){int d=p<q?1:-1;while(p!=q){cout<<*p<<", ";p+=d;}cout<<endl;}
//#endif
template<typename T>bool umax(T&a, const T&b){return b<=a?false:(a=b,true);}
template<typename T>bool umin(T&a, const T&b){return b>=a?false:(a=b,true);}
template<typename T>
void V2A(T a[],const vector<T>&b){for(int i=0;i<b.size();i++)a[i]=b[i];}
template<typename T>
void A2V(vector<T>&a,const T b[]){for(int i=0;i<a.size();i++)a[i]=b[i];}#if 0
const double PI = acos(-1.0);
const int INF = 1e9 + 7;
const double EPS = 1e-8;
#endif/* -------------------------------------------------------------------------------- */const int maxn = 4e5 + 7;int u[maxn], v[maxn], w[maxn], tot;
pii rem[maxn];class TA {int C[maxn], n;inline int lowbit(int x) { return x & -x; }
public:void init(int n) {this->n = n;for (int i = 1; i <= n; i ++) C[i] = 0;}void update(int p, int x) {while (p <= n) {C[p] += x;p += lowbit(p);}}int query(int p) {int ans = 0;while (p) {ans += C[p];p -= lowbit(p);}return ans;}
};
TA lta, rta;inline int find(int x) {return lower_bound(w, w + tot, x) - w + 1;
}int main() {
#ifndef ONLINE_JUDGEfreopen("in.txt", "r", stdin);//freopen("out.txt", "w", stdout);
#endif // ONLINE_JUDGEint cas = 0, n;while (cin >> n) {tot = 0;int len = 1;for (int i = 0; i < n; i ++) {scanf("%d%d", u + i, v + i);if (u[i] == 0) {rem[len] = mp(v[i], v[i] + len);w[tot ++] = v[i];w[tot ++] = v[i] + len ++;}}sort(w, w + tot);tot = unique(w, w + tot) - w;lta.init(tot);rta.init(tot);printf("Case #%d:\n", ++ cas);len = 1;for (int i = 0; i < n; i ++) {if(u[i] == 1) {pii buf = rem[v[i]];int lid = find(buf.X), rid = find(buf.Y);lta.update(lid, - 1);rta.update(rid, - 1);}else {int lid = find(v[i]), rid = find(v[i] + len ++);printf("%d\n", rta.query(rid) - lta.query(lid - 1));lta.update(lid, 1);rta.update(rid, 1);}}}return 0;
}