Submission #1321659

#	Time	Username	Problem	Language	Result	Execution time	Memory
1321659		kasamchi	The Big Prize (IOI17_prize)	C++20	20 / 100	624 ms	1114112 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>
using namespace std;

vector<vector<int>> buf;

vector<int> qry(int x) {
    if (buf[x].empty()) {
        return buf[x] = ask(x);
    } else {
        return buf[x];
    }
}

int bcnt;
vector<int> tar;

void dfs(int l, int r, int cnt, int lp, int rs) {
    if (l == r) {
        tar.push_back(l);
    } else {
        int rm = l + (r - l) / 2, lm = rm;
        vector<int> res = qry(lm);
        while (res[0] + res[1] < bcnt) {
            tar.push_back(lm);
            lm--;
            if (lm < l) {
                break;
            }
            res = qry(lm);
        }
        int lc = res[0] - lp;
        if (lc > 0) {
            dfs(l, lm - 1, lc, lp, res[1]);
        }

        lm = rm;
        res = qry(lm);
        while (res[0] + res[1] < bcnt) {
            tar.push_back(lm);
            lm++;
            if (lm > r) {
                break;
            }
            res = qry(lm);
        }
        int rc = res[1] - rs;
        if (rc > 0) {
            dfs(lm + 1, r, rc, res[0], rs);
        }
    }
}

int find_best(int n) {
    buf.clear(), buf.resize(n);

    vector<int> rng;
    for (int i = 0; i < n; i++) {
        rng.push_back(i);
    }
    random_shuffle(rng.begin(), rng.end());
    for (int i = 0; i < min(n, 200); i++) {
        vector<int> res = qry(rng[i]);
        bcnt = max(bcnt, res[0] + res[1]);
    }
    dfs(0, n - 1, bcnt, 0, 0);

    for (int x : tar) {
        vector<int> res = qry(x);
        if (res[0] + res[1] == 0) {
            return x;
        }
    }
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:61:19: warning: 'void std::random_shuffle(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<int*, vector<int> >]' is deprecated: use 'std::shuffle' instead [-Wdeprecated-declarations]
   61 |     random_shuffle(rng.begin(), rng.end());
      |     ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/13/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:51,
                 from prize.cpp:2:
/usr/include/c++/13/bits/stl_algo.h:4581:5: note: declared here
 4581 |     random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
      |     ^~~~~~~~~~~~~~
prize.cpp:74:1: warning: control reaches end of non-void function [-Wreturn-type]
   74 | }
      | ^

• Subtask 1: 20 / 20
• Subtask 2: 0 / 80