Submission #428315

#	Time	Username	Problem	Language	Result	Execution time	Memory
428315		Popax21	Finding Routers (IOI20_routers)	C++14	69.65 / 100	2 ms	300 KiB

routers

#include <stdio.h>
#include "routers.h"

int bsearch(int l, int r, int n) {
    if(l == r-1) return l;
    int m = l + (r - l) / 2;

    int mr = use_detector(m);
    if(mr != n) return bsearch(l, m, n);
    else return bsearch(m, r, n);
}

std::vector<int> find_routers(int l, int n, int q) {
    std::vector<int> rs(n);
    rs[0] = 0;

    int pr = 0;
    for(int c = 1; c < n; c++) {
        int p = bsearch(rs[pr]+1, l+1, pr)+1;
        int r = use_detector(p);

        rs[r] = 2*p - rs[pr];
        if(r > pr) rs[r] -= 2;

        // printf("pr %d r %d p %d pp %d p' %d\n", pr, r, p, rs[pr], rs[r]);
        pr = r;
    }

    return rs;
}

• Subtask 1: 16 / 16
• Subtask 2: 21 / 21
• Subtask 3: 23 / 23
• Subtask 4: 9.654399999999999 / 40