【NOIP 2017 普及组】 跳房子

裸的单调队列优化dp+二分

我居然还调了挺久

日常审题错误

 #include <bits/stdc++.h>

 using namespace std;

 typedef long long ll;

 const ll inf = 1e9, MAXN = 5e5 + ;

 ll f[MAXN], x[MAXN], c[MAXN], d, n;

 struct mque {
     deque <int> q;

     void push(int x) {
         while(!q.empty() && f[q.back()] <= f[x]) q.pop_back();
         q.push_back(x);
     }
     void pop_front() {q.pop_front();}
     int front() {return q.front();}
     bool empty() {return q.empty();}
     void clear() {q.clear();}

 } que;

 ll dp(ll g) {
     memset(f, ~0x3f, sizeof(f));
     ll ans = , now = ;
     que.clear();
     f[] = ;
     for(int i = ; i <= n; i++) {
         for(; now < i && x[i] - x[now] >= d - g; now++) que.push(now);
         while(!que.empty() && x[i] - x[que.front()] > d + g) que.pop_front();
         if(que.empty()) continue;
         f[i] = f[que.front()] + c[i];
         ans = max(f[i], ans);
     }
     return ans;
 }

 int main() {
     ios::sync_with_stdio(false);
     ll k, l = , r = inf;
     cin >> n >> d >> k;
     for(int i = ; i <= n; i++)
         cin >> x[i] >> c[i];
     while(l < r) {
         ll mid = (l + r) / ;
         if(dp(mid) < k) l = mid + ;
         else r = mid;
     }
     cout << l << endl;
     return ;
 }