Submission #1116830

#	Time	Username	Problem	Language	Result	Execution time	Memory
1116830		SalihSahin	Shortcut (IOI16_shortcut)	C++14	0 / 100	1 ms	348 KiB

shortcut

#include <bits/stdc++.h>
#define pb push_back
using namespace std;
#include "shortcut.h"

long long inf = 1e18;

 
long long find_shortcut(int n, vector<int> l, vector<int> d, int c){
    vector<long long> pre(n);
    for(int i = 0; i < n-1; i++){
        pre[i+1] = pre[i] + l[i];
    }
    vector<long long> lfar(n), rfar(n);
    lfar[0] = d[0];
    for(int i = 1; i < n; i++){
        if(d[i] > lfar[i-1] + l[i-1]) lfar[i] = d[i];
        else lfar[i] = lfar[i-1] + l[i-1];
    }
    rfar[n-1] = d[n-1];
    for(int i = n-2; i >= 0; i--){
        if(d[i] > rfar[i+1] + l[i]) rfar[i] = d[i];
        else rfar[i] = rfar[i+1] + l[i];
    }
 
    vector<long long> precalcl(n), precalcr(n);
    for(int i = 1; i < n; i++){
        precalcl[i] = max(precalcl[i-1], (long long)(lfar[i-1] + l[i-1] + d[i]));
    }
    for(int i = n-2; i >= 0; i--){
        precalcr[i] = max(precalcr[i+1], (long long)(rfar[i+1] + l[i] + d[i]));
    }
 
    long long ans;
    long long val = 0;
    for(int i = 0; i < n-1; i++){
        val = max(val, lfar[i] + rfar[i+1] + l[i]);
    }
    ans = val;
 
    for(int l = 0; l < n-1; l++){
        long long maxla = precalcl[l];

        long long L = maxla, R = ans;
        while(L < R){
            long long M = (L + R)/2;

            int limr2 = n-1;
            for(int j = l+1; j < n; j++){
                long long clen = (pre[j] - pre[l] + c);
                long long val = lfar[l] + (long long)d[j] + min(pre[j] - pre[l], clen - (pre[j] - pre[l]));
                if(val > M) limr2 = j-1;
            } // L-M

            if(limr2 < l+1){
                L = M+1;
                continue;
            }

            int l2 = l+1, r2 = limr2;
            while(l2 < r2){
                int r = (l2 + r2)/2;
                long long dis1 = 0;
                dis1 = lfar[l] + rfar[r] + c; // L-R
                dis1 = max(dis1, precalcr[r]); // R-R
                if(dis1 <= M) r2 = r;
                else l2 = r + 1;
            }
            int shouldbiggerthan = l2;

            l2 = l+1, r2 = limr2;
            while(l2 < r2){
                int r = (l2 + r2 + 1)/2;
                long long dis2 = 0;
                long long clen = pre[r] - pre[l] + c;
                
                for(int j = l+1; j <= r; j++){
                    dis2 = max(dis2, lfar[l] + (long long)d[j] + min(pre[j] - pre[l], clen - (pre[j] - pre[l])));
                } // L-M
                for(int j = l; j < r; j++){
                    dis2 = max(dis2, rfar[r] + (long long)d[j] + min(pre[r] - pre[j], clen - (pre[r] - pre[j])));
                } // R-M
     
                for(int j = l+1; j < r; j++){ // M-M
                    long long addj = d[j];
                    for(int j2 = j+1; j2 < r; j2++){
                        long long addj2 = d[j2];
                        dis2 = max(dis2, min(pre[j2] - pre[j], clen - (pre[j2] - pre[j])) + addj + addj2);
                    }
                }

                if(dis2 <= M) l2 = r;
                else r2 = r - 1;
            }
            int shouldsmallerthan = l2;
            //cout<<l<<" deyiz.     -> "<<M<<" icin denedik => "<<shouldbiggerthan<<" "<<shouldsmallerthan<<endl;
            if(shouldbiggerthan <= shouldsmallerthan){
                bool check = 1;
                int r = shouldbiggerthan;

                long long dis = lfar[l] + rfar[r] + min((long long)c, pre[r] - pre[l]); // L-R
                dis = max(dis, precalcl[l]); // L-L
                dis = max(dis, precalcr[r]); // R-R
                long long clen = pre[r] - pre[l] + c;
                
                for(int j = l+1; j <= r; j++){
                    dis = max(dis, lfar[l] + (long long)d[j] + min(pre[j] - pre[l], clen - (pre[j] - pre[l])));
                } // L-M
                for(int j = l; j < r; j++){
                    dis = max(dis, rfar[r] + (long long)d[j] + min(pre[r] - pre[j], clen - (pre[r] - pre[j])));
                } // R-M
     
                for(int j = l+1; j < r; j++){ // M-M
                    long long addj = d[j];
                    for(int j2 = j+1; j2 < r; j2++){
                        long long addj2 = d[j2];
                        dis = max(dis, min(pre[j2] - pre[j], clen - (pre[j2] - pre[j])) + addj + addj2);
                    }
                }

                if(dis > M) check = 0;

                if(check) R = M;
                else L = M + 1;
            }
            else L = M + 1;
        }

        ans = min(ans, L);
    }
 
    return ans;
}

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