HDU 5360 Hiking (贪心)

时间：2024-08-23 19:06:08

题意：邀请 n 参加聚会，如果在邀请第 i 个人之前，已经成功邀请了 x 个人，并且 li <= x <= ri，那么第 i 人才会去，问你怎么排列使得邀请的人最多。

析：对于所有的人，按照 li 进行排序，对于维护一个优先队列，队列内是 ri 小的优先，然后枚举每个时间点，把 li 等于的当前时间点的都放到队列中，然后取出最优先那个，这就是要邀请的，当然如果队列顶上的 ri 小于当前时间点，要把它从队列中删除。

代码如下：

#pragma comment(linker, "/STACK:1024000000,1024000000")

#include <cstdio>

#include <string>

#include <cstdlib>

#include <cmath>

#include <iostream>

#include <cstring>

#include <set>

#include <queue>

#include <algorithm>

#include <vector>

#include <map>

#include <cctype>

#include <cmath>

#include <stack>

#include <sstream>

#include <list>

#include <assert.h>

#include <bitset>

#include <numeric>

#define debug() puts("++++")

#define gcd(a, b) __gcd(a, b)

#define lson l,m,rt<<1

#define rson m+1,r,rt<<1|1

#define fi first

#define se second

#define pb push_back

#define sqr(x) ((x)*(x))

#define ms(a,b) memset(a, b, sizeof a)

#define sz size()

#define be begin()

#define ed end()

#define pu push_up

#define pd push_down

#define cl clear()

#define lowbit(x) -x&x

//#define all 1,n,1

#define FOR(i,n,x)  for(int i = (x); i < (n); ++i)

#define freopenr freopen("in.in", "r", stdin)

#define freopenw freopen("out.out", "w", stdout)

using namespace std;

typedef long long LL;

typedef unsigned long long ULL;

typedef pair<int, int> P;

const int INF = 0x3f3f3f3f;

const LL LNF = 1e17;

const double inf = 1e20;

const double PI = acos(-1.0);

const double eps = 1e-8;

const int maxn = 1e5 + 20;

const int maxm = 1e6 + 10;

const LL mod = 1000000000000000LL;

const int dr[] = {-1, 1, 0, 0, 1, 1, -1, -1};

const int dc[] = {0, 0, 1, -1, 1, -1, 1, -1};

const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};

int n, m;

const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

inline bool is_in(int r, int c) {

  return r >= 0 && r < n && c >= 0 && c < m;

}

inline int readInt(){ int x;  scanf("%d", &x);  return x; }

struct Node{

  int l, r, id;

  bool operator < (const Node &rhs) const{

    return r > rhs.r;

  }

};

Node a[maxn];

bool vis[maxn];

int main(){

  int T;  cin >> T;

  while(T--){

    scanf("%d", &n);

    for(int i = 0; i < n; ++i){

      scanf("%d", &a[i].l);

      a[i].id = i;

    }

    for(int i = 0; i < n; ++i)  scanf("%d", &a[i].r);

    sort(a, a + n, [&](Node a, Node b){ return a.l < b.l; });

    priority_queue<Node> pq;

    vector<int> ans;

    int k = 0;

    for(int i = 0; i < n; ++i){

      while(ans.sz == i && k < n && a[k].l == i)  pq.push(a[k++]);

      while(!pq.empty() && pq.top().r < i)  pq.pop();

      if(pq.empty())  continue;

      ans.pb(pq.top().id);  pq.pop();

    }

    printf("%d\n", ans.sz);

    int cnt = 0;  ms(vis, 0);

    for(int i = 0; i < ans.sz; ++i){

      vis[ans[i]] = 1;

      if(cnt)  printf(" %d", ans[i] + 1);

      else printf("%d", ans[i] + 1);

      cnt = 1;

    }

    for(int i = 0; i < n; ++i)  if(!vis[i]){

      if(cnt)  printf(" %d", i + 1);

      else printf("%d", i + 1);

      cnt = 1;

    }

    printf("\n");

  }

  return 0;

}

　　

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