Submission #40215

#	Time	Username	Problem	Language	Result	Execution time	Memory
40215		jackyliuxx	The Big Prize (IOI17_prize)	C++14	97.41 / 100	32 ms	2420 KiB

prize

#include "prize.h"
// #include <iostream>
#include <map>
using namespace std;

map<int, map<int, pair<int, int>>> resmap;

void resmap_push(int i, int lc, int rc) {
    resmap[lc + rc][i] = {lc, rc};
}

int gogo(int fr, int to, int lc, int rc, int mxc) {
    // cout << "go " << fr << ' ' << to << endl;
    if (lc + rc == mxc) {
        return -1;
    }
    for (auto &rsmp : resmap) {
        auto &mp = rsmp.second;
        auto lb = mp.lower_bound(fr);
        auto ub = mp.upper_bound(to);
        pair<int, int> lres, rres;
        // cout << "check " << rsmp.first << endl;
        if (lb == mp.begin()) {
            // cout << "no lb" << endl;
            lres = {0, rsmp.first};
        } else {
            lb--;
            // cout << "lb " << lb->first << endl;
            lres = lb->second;
        }
        if (ub == mp.end()) {
            // cout << "no ub" << endl;
            rres = {rsmp.first, 0};
        } else {
            // cout << "ub " << ub->first << endl;
            rres = ub->second;
        }
        if (lres.first == rres.first) {
            // cout << "skip" << endl;
            return -1;
        }
    }
    int mid = (fr + to) / 2;
    int lto = mid, rfr = mid + 1;
    vector<int> res;
    int n = to - fr;
    for (int i = 0; i < n; i++) {
        if (i & 1) {
            mid -= i;
        } else {
            mid += i;
        }
        lto = min(lto, mid);
        rfr = max(rfr, mid + 1);
        res = ask(mid);
        resmap_push(mid, res[0], res[1]);
        int c = res[0] + res[1];
        if (c == 0) {
            return mid;
        } else if (c == mxc) {
            int lrc, rlc;
            if (mid == lto) {
                lrc = res[1];
                rlc = res[0] + i;
            } else {
                lrc = res[1] + i;
                rlc = res[0];
            }
            return max(gogo(fr, lto, lc, lrc, mxc), gogo(rfr, to, rlc, rc, mxc));
        }
    }
    return -1;
}

int find_best(int n) {
    resmap.clear();
    int mxc = 0;
    int lc = 0;
    for(int i = 0; i < n && i < 500; i++) {
		std::vector<int> res = ask(i);
        resmap_push(i, res[0], res[1]);
        lc = res[0];
		if(res[0] + res[1] == 0)
			return i;
        if (res[0] + res[1] > mxc) {
            mxc = res[0] + res[1];
        }
    }
    return gogo(0, n, 0, 0, mxc);
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:78:9: warning: variable 'lc' set but not used [-Wunused-but-set-variable]
     int lc = 0;
         ^

• Subtask 1: 20 / 20
• Subtask 2: 77.41 / 80