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  • URAL-1987 Nested Segments 线段树简单区间覆盖

      题目链接:http://acm.timus.ru/problem.aspx?space=1&num=1987

      题意:给定n条线段,每两条线段要么满足没有公共部分,要么包含。给出m个询问,求当前点被覆盖的最小长度的线段编号。

      由于线段不存在部分相交的情况,因此,直接按照输入顺序覆盖区间就可以了,因为后覆盖的线段更短。

      1 //STATUS:C++_AC_187MS_6805KB
      2 #include <functional>
      3 #include <algorithm>
      4 #include <iostream>
      5 //#include <ext/rope>
      6 #include <fstream>
      7 #include <sstream>
      8 #include <iomanip>
      9 #include <numeric>
     10 #include <cstring>
     11 #include <cassert>
     12 #include <cstdio>
     13 #include <string>
     14 #include <vector>
     15 #include <bitset>
     16 #include <queue>
     17 #include <stack>
     18 #include <cmath>
     19 #include <ctime>
     20 #include <list>
     21 #include <set>
     22 #include <map>
     23 using namespace std;
     24 //#pragma comment(linker,"/STACK:102400000,102400000")
     25 //using namespace __gnu_cxx;
     26 //define
     27 #define pii pair<int,int>
     28 #define mem(a,b) memset(a,b,sizeof(a))
     29 #define lson l,mid,rt<<1
     30 #define rson mid+1,r,rt<<1|1
     31 #define PI acos(-1.0)
     32 //typedef
     33 typedef __int64 LL;
     34 typedef unsigned __int64 ULL;
     35 //const
     36 const int N=100010;
     37 const int INF=0x3f3f3f3f;
     38 const int MOD=95041567,STA=8000010;
     39 const LL LNF=1LL<<60;
     40 const double EPS=1e-8;
     41 const double OO=1e15;
     42 const int dx[4]={-1,0,1,0};
     43 const int dy[4]={0,1,0,-1};
     44 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
     45 //Daily Use ...
     46 inline int sign(double x){return (x>EPS)-(x<-EPS);}
     47 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
     48 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
     49 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
     50 template<class T> inline T Min(T a,T b){return a<b?a:b;}
     51 template<class T> inline T Max(T a,T b){return a>b?a:b;}
     52 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
     53 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
     54 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
     55 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
     56 //End
     57 
     58 int c[(N*3)<<2],t[N][2],q[N],id[N*3];
     59 int n;
     60 
     61 void pushdown(int rt)
     62 {
     63     if(c[rt]!=-1)
     64         c[rt<<1]=c[rt<<1|1]=c[rt];
     65 }
     66 
     67 void pushup(int rt)
     68 {
     69     if(c[rt<<1]==c[rt<<1|1])
     70         c[rt]=c[rt<<1];
     71     else c[rt]=-1;
     72 }
     73 
     74 void update(int l,int r,int rt,int L,int R,int val)
     75 {
     76     if(L<=l && r<=R){
     77         c[rt]=val;
     78         return;
     79     }
     80     pushdown(rt);
     81     int mid=(l+r)>>1;
     82     if(L<=mid)update(lson,L,R,val);
     83     if(R>mid)update(rson,L,R,val);
     84     pushup(rt);
     85 }
     86 
     87 int query(int l,int r,int rt,int w)
     88 {
     89     if(l==r){
     90         return c[rt];
     91     }
     92     pushdown(rt);
     93     int mid=(l+r)>>1,ret;
     94     if(w<=mid)ret=query(lson,w);
     95     else ret=query(rson,w);
     96     pushup(rt);
     97     return ret;
     98 }
     99 
    100 int main()
    101 {
    102  //   freopen("in.txt","r",stdin);
    103     int i,j,k,L,R,m;
    104     while(~scanf("%d",&n))
    105     {
    106         k=0;
    107         for(i=1;i<=n;i++){
    108             scanf("%d%d",&t[i][0],&t[i][1]);
    109             id[k++]=t[i][0];
    110             id[k++]=t[i][1];
    111         }
    112         scanf("%d",&m);
    113         for(i=0;i<m;i++){
    114             scanf("%d",&q[i]);
    115             id[k++]=q[i];
    116         }
    117         sort(id,id+k);
    118         k=unique(id,id+k)-id;
    119         mem(c,-1);
    120         for(i=1;i<=n;i++){
    121             L=lower_bound(id,id+k,t[i][0])-id+1;
    122             R=lower_bound(id,id+k,t[i][1])-id+1;
    123             update(1,k,1,L,R,i);
    124         }
    125 
    126         for(i=0;i<m;i++){
    127             printf("%d
    ",query(1,k,1,lower_bound(id,id+k,q[i])-id+1));
    128         }
    129     }
    130     return 0;
    131 }
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  • 原文地址:https://www.cnblogs.com/zhsl/p/3395876.html
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