제출 #784736

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
784736		YassirSalama	Shortcut (IOI16_shortcut)	C++14	0 / 100	1 ms	340 KiB

shortcut

#include "shortcut.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long
const ll MAXN=5100;
const ll INF=1e9+10;
#define dbg(x) cout<<" [ "<<#x<<" ] : "<<x<<endl;
#define F first
#define S second
#define all(v) v.begin(),v.end()
long long find_shortcut(int n, vector<int> l, vector<int> d, int c)
{
    if(n==2){
        if(c<l[0])
            return d[0]+c+d[1];
        return d[0]+l[0]+d[1];
    }
    vector<int> pref(MAXN+1,0);
    for(int i=0;i<n-1;i++){
        pref[i+1]=pref[i]+l[i];
    }
    vector<int> left(MAXN+1,0);
    vector<int> right(MAXN+1,0);
    //the idea is to use pref[i-1]+l[i] or d[i]
    left[0]=d[0];
    int first_node=0;
    for(int i=1;i<n;i++){
        if(d[i]>left[i-1]+l[i-1]) first_node=i;
        left[i]=max(left[i-1]+l[i-1],d[i]);
    }
    int last_node=n-1;
    right[n-1]=d[n-1];
    for(int i=n-2;i>=0;i--){
        if(d[i]>right[i+1]+l[i]) last_node=i;
        right[i]=max(right[i+1]+l[i],d[i]);
    }
    vector<int> nodes;//nodes in the diameter
    // cout<<first_node<<" "<<last_node<<endl;
    int diameter=left[first_node]+right[first_node];
    // cout<<diameter<<endl;
    for(int i=first_node;i<=last_node;i++){
        for(int j=i+1;j<=last_node;j++){
            int express=left[i]+c+right[j];
            int newdiameter=0;
            for(int k=0;k<=n-1;k++){
                newdiameter=max(newdiameter,abs(pref[j]-pref[k])+right[j]);
            }
            for(int k=n-1;k>=0;k--){
                newdiameter=max(newdiameter,abs(pref[k]-pref[i])+left[i]);
            }
            // if(i==0&&j==7){
                // cout<<pref[j]-
            // }
            // cout<<newdiameter<<" "<<express<<" "<<i<<" "<<j<<endl;
            // if(newdiameter>express) continue;
            diameter=min({max(newdiameter,express),diameter});
        }
    }
    // cout<<c<<endl;
    return diameter;
}

// int main()
// {
//     int n, c;
//     assert(2 == scanf("%d%d", &n, &c));
    
//     std::vector<int> l(n - 1);
//     std::vector<int> d(n);
//     for (int i = 0; i < n - 1; i++)
//         assert(1 == scanf("%d", &l[i]));
//     for (int i = 0; i < n; i++)
//         assert(1 == scanf("%d", &d[i]));
        
//     long long t = find_shortcut(n, l, d, c);
    
    
//     printf("%lld\n", t);
    
//     return 0;
// }

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