Submission #129011

#	Time	Username	Problem	Language	Result	Execution time	Memory
129011		Plurm	Cake 3 (JOI19_cake3)	C++11	24 / 100	4026 ms	4708 KiB

cake3

#include <bits/stdc++.h>
using namespace std;
int n,m;
vector<pair<int,int> > pieces;
long long query(int l, int r){
    vector<int> v;
    for(int i = l+1; i < r; i++){
        v.push_back(pieces[i].first);
    }
    sort(v.begin(), v.end());
    long long sum = pieces[l].first + pieces[r].first;
    for(int i = 2; i < m; i++){
        sum += 1ll * v.back();
        v.pop_back();
    }
    return sum;
}
long long solve(int l, int r, int lb, int rb){
    int mid = (l + r)/2;
    long long ans = -1e18;
    int mindex = -1;
    for(int i = lb; i <= min(mid-m+1,rb); i++){
        long long cur = query(i, mid) + 2ll * pieces[i].second - 2ll * pieces[mid].second;
        if(cur > ans){
            ans = cur;
            mindex = i;
        }
    }
    if(l <= mid-1) ans = max(ans, solve(l, mid-1, lb, mindex == -1 ? rb : mindex));
    if(mid+1 <= r) ans = max(ans, solve(mid+1, r, mindex == -1 ? lb : mindex, rb));
    return ans;
}
int main(){
    scanf("%d%d",&n,&m);
    int v,c;
    for(int i = 0; i < n; i++){
        scanf("%d%d",&v,&c);
        pieces.emplace_back(v,c);
    }
    stable_sort(pieces.begin(), pieces.end(), [](pair<int,int> x, pair<int,int> y){
        return x.second < y.second;
    });
    long long ans = solve(m-1,n-1,0,n-1);
    printf("%lld\n",ans);
    return 0;
}

Compilation message (stderr)

cake3.cpp: In function 'int main()':
cake3.cpp:34:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
cake3.cpp:37:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&v,&c);
         ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 0 / 76