Submission #790733

#	Time	Username	Problem	Language	Result	Execution time	Memory
790733		peteza	Meetings (IOI18_meetings)	C++14	19 / 100	561 ms	8504 KiB

meetings

#include "meetings.h"
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;

struct stk {
    long long sum = 0;
    stack<pii> st;
    stk():sum(0){while(!st.empty())st.pop();}
    void add(int x) {
        int cur = 1;
        while(!st.empty() && st.top().first <= x) {
            cur += st.top().second;
            sum -= 1ll*st.top().first*st.top().second;
            st.pop();
        }
        st.emplace(x, cur);
        sum += 1ll*x*cur;
    }
} ls, rs;

long long l[5005], r[5005];

struct dat {
    int L, R, ans;
    bool allone;
    dat(){L=R=ans=allone=0;}
    dat(int x){allone=L=R=ans=(x==1);}
} segm[400005];

dat operator+(dat a, dat b) {
    dat ret;
    ret.allone = (a.allone && b.allone);
    ret.L = (a.allone ? a.L + b.L : a.L);
    ret.R = (b.allone ? b.R + a.R : b.R);
    ret.ans = max({a.ans, b.ans, a.R + b.L});
    return ret;
}

void build(int idx, int l, int r, vector<int>& ans) {
    if(l == r)
        segm[idx] = dat(ans[l]);
    else {
        int mid = (l+r) >> 1;
        build(idx*2+1, l, mid, ans);
        build(idx*2+2, mid+1, r, ans);
        segm[idx] = segm[idx*2+1] + segm[idx*2+2];
    }
}

dat qr(int idx, int l, int r, int tl, int tr) {
    if(tl <= l && r <= tr) return segm[idx];
    if(tr < l || r < tl) return dat();
    int mid = (l+r) >> 1;
    return qr(idx*2+1, l, mid, tl, tr) + qr(idx*2+2, mid+1, r, tl, tr);
}

std::vector<long long> minimum_costs(std::vector<int> H, std::vector<int> L,
                                     std::vector<int> R) {
  int Q = L.size();
  std::vector<long long> C(Q);
    if(*max_element(H.begin(), H.end()) <= 2) {
        int l=-1,r=-1;
        for(int cq=0;cq<Q;cq++) {
            C[cq] = 2*(R[cq]-L[cq]+1) - qr(0, 0, H.size()-1, L[cq], R[cq]).ans;
        }
        return C;
    }
  for (int j = 0; j < Q; ++j) {
    C[j] = __LONG_LONG_MAX__;
    ls = stk(); rs = stk();
    for(int i=L[j];i<=R[j];i++) {
        ls.add(H[i]); l[i] = ls.sum;
    }
    for(int i=R[j];i>=L[j];i--) {
        rs.add(H[i]); r[i] = rs.sum;
    }
    for(int i=L[j];i<=R[j];i++) {
        C[j] = min(C[j], l[i] + r[i] - H[i]);
    }
  }
  return C;
}

/*
4 2
2 4 3 5
0 2
1 3
*/

Compilation message (stderr)

meetings.cpp: In constructor 'dat::dat(int)':
meetings.cpp:28:24: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   28 |     dat(int x){allone=L=R=ans=(x==1);}
      |                       ~^~~~~~~~~~~~~
meetings.cpp: In function 'std::vector<long long int> minimum_costs(std::vector<int>, std::vector<int>, std::vector<int>)':
meetings.cpp:63:13: warning: unused variable 'l' [-Wunused-variable]
   63 |         int l=-1,r=-1;
      |             ^
meetings.cpp:63:18: warning: unused variable 'r' [-Wunused-variable]
   63 |         int l=-1,r=-1;
      |                  ^

• Subtask 1: 4 / 4
• Subtask 2: 15 / 15
• Subtask 3: 0 / 17
• Subtask 4: 0 / 24
• Subtask 5: 0 / 40