bnu36905 Nested Segments 离散化+线段树

标签：线段树

bnu36905 Nested Segments

离散化+线段树区间更新

也可以用离散化+set（或双向链表）

#include <cstdio>
#include <ctime>
#include <cstdlib>
#include <cstring>
#include <queue>
#include <string>
#include <set>
#include <stack>
#include <map>
#include <cmath>
#include <vector>
#include <iostream>
#include <algorithm>
#include <bitset>
#include <fstream>
using namespace std;
//LOOP
#define FF(i, a, b) for(int i = (a); i < (b); ++i)
#define FE(i, a, b) for(int i = (a); i <= (b); ++i)
#define FED(i, b, a) for(int i = (b); i>= (a); --i)
#define REP(i, N) for(int i = 0; i < (N); ++i)
#define CLR(A,value) memset(A,value,sizeof(A))
#define FC(it, c) for(__typeof((c).begin()) it = (c).begin(); it != (c).end(); it++)
//OTHER
#define SZ(V) (int)V.size()
#define PB push_back
#define MP make_pair
#define all(x) (x).begin(),(x).end()
//INPUT
#define RI(n) scanf("%d", &n)
#define RII(n, m) scanf("%d%d", &n, &m)
#define RIII(n, m, k) scanf("%d%d%d", &n, &m, &k)
#define RIV(n, m, k, p) scanf("%d%d%d%d", &n, &m, &k, &p)
#define RV(n, m, k, p, q) scanf("%d%d%d%d%d", &n, &m, &k, &p, &q)
#define RS(s) scanf("%s", s)

#define sqr(x) (x) * (x)
typedef long long LL;
typedef unsigned long long ULL;
typedef vector <int> VI;
const int INF = 0x3f3f3f3f;
const double EPS = 1e-9;
const int MOD = 1000000007;
const double PI = acos(-1.0);

const int maxn = 410000;
#define ll rt << 1
#define rr rt << 1 | 1
struct Node{
    int l, r, m;
    int val;
}st[maxn << 2];
void build(int l, int r, int rt)
{
    st[rt].l = l; st[rt].r = r;
    int m = (l + r) >> 1; st[rt].m = m;
    st[rt].val = -1;
    if (l == r) return ;
    build(l, m, ll); build(m + 1, r, rr);
}
inline void segVal(int rt, int x)
{
    st[rt].val = x;
}
inline void down(int rt)
{
    if (st[rt].val != -1)
    {
        segVal(ll, st[rt].val);
        segVal(rr, st[rt].val);
        st[rt].val = -1;
    }
}
void update(int L, int R, int x, int rt)
{
    if (L <= st[rt].l && st[rt].r <= R)
    {
        segVal(rt, x);
        return ;
    }
    down(rt);
    if (L <= st[rt].m) update(L, R, x, ll);
    if (R > st[rt].m) update(L, R, x, rr);
}
int query(int p, int rt)
{
    if (st[rt].l == st[rt].r)
        return st[rt].val;
    down(rt);
    if (p <= st[rt].m) return query(p, ll);
    else return query(p, rr);
}
int n;
struct Seg{
    int l, r;
    int id;
    bool operator<(const Seg &rhs) const{
        return r - l > rhs.r - rhs.l;
    }
}seg[100010];
int a[maxn];
int asz;
int main()
{
    while (~RI(n))
    {
        asz = 0;
        REP(i, n)
        {
            scanf("%d%d", &seg[i].l, &seg[i].r);
            a[asz++] = seg[i].l; a[asz++] = seg[i].r;
            seg[i].id = i + 1;
        }
        sort(seg, seg + n);

        ///离散化start
        a[asz++] = 0; a[asz++] = 1e9 + 1;
        sort(a, a + asz);
        asz = unique(a, a + asz) - a;
        int atot = asz;
        for (int i = 1; i < asz; i++)
        {
            if (a[i] - a[i - 1] > 1) a[atot++] = a[i] - 1;///
        }
        asz = atot;
        sort(a, a + asz);
        ///离散化end

        build(1, asz, 1);
        for (int i = 0; i < n; i++)
        {
            int L = lower_bound(a, a + asz, seg[i].l) - a;
            int R = lower_bound(a, a + asz, seg[i].r) - a;
            update(L + 1, R + 1, seg[i].id, 1);
        }
        int q;
        RI(q);
        while (q--)
        {
            int x;
            RI(x);
            int xx = lower_bound(a, a + asz, x) - a;
            printf("%d\n", query(xx + 1, 1));
        }
    }
    return 0;
}

bnu36905 Nested Segments 离散化+线段树,布布扣,bubuko.com

bnu36905 Nested Segments 离散化+线段树

标签：线段树

原文地址：http://blog.csdn.net/guognib/article/details/38497245