Submission #595367

#	Time	Username	Problem	Language	Result	Execution time	Memory
595367		Lucpp	Shortcut (IOI16_shortcut)	C++17	71 / 100	1916 ms	524288 KiB

shortcut

#include "shortcut.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18;

int n;
vector<ll> x;

bool solve(const vector<tuple<ll, ll, ll>>& sq){
    ll a = -INF, b = INF, c = INF, d = -INF;
    for(auto [xc, yc, r] : sq){
        a = max(a, xc-r-yc);
        b = min(b, xc+r-yc);
        c = min(c, xc+r+yc);
        d = max(d, xc-r+yc);
    }
    if(a > b || c < d) return false;
    int lo = 0, hi = n-1;
    for(int i = 0; i < n; i++){
        ll ylo = max(x[i]-b, d-x[i]);
        ll yhi = min(x[i]-a, c-x[i]);
        if(lo == -1) lo++;
        if(hi == n) hi--;
        while(lo < n-1 && x[lo] < ylo) lo++;
        while(lo >= 0 && x[lo] >= ylo) lo--;
        while(hi > 0 && x[hi] > yhi) hi--;
        while(hi < n && x[hi] <= yhi) hi++;
        if(hi-lo > 1) return true;
    }
    return false;
}

ll find_shortcut(int n_, vector<int> len, vector<int> d, int c) {
    n = n_;
    x.resize(n);
    x[0] = 0;
    for(int i = 0; i < n-1; i++) x[i+1] = x[i]+len[i];
    ll M = x.back()+*max_element(d.begin(), d.end())*2;
    ll lo = 0, hi = M;
    for(ll mid=(lo+hi)/2; lo<hi; mid=(lo+hi)/2){
        vector<tuple<ll, ll, ll>> sq;
        for(int i = 0; i < n; i++){
            for(int j = i+1; j < n; j++){
                if(abs(x[i]-x[j])+d[i]+d[j] <= mid) continue;
                sq.emplace_back(x[i], x[j], mid-c-d[i]-d[j]);
            }
        }
        if(solve(sq)) hi = mid;
        else lo = mid+1;
    }
    return lo;
}

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 33 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3