Submission #784068

#	Time	Username	Problem	Language	Result	Execution time	Memory
784068		zsombor	Unscrambling a Messy Bug (IOI16_messy)	C++17	100 / 100	2 ms	468 KiB

messy

#include <iostream>
#include <vector>
#include "messy.h"
using namespace std;

string s = "";

char opp(int i) {
    return (s[i] == '0' ? '1' : '0');
}

vector <int> restore_permutation(int n, int w, int r) {
    int l; for (int j = 0; j <= 7; j++) if (n & (1 << j)) l = j;
    for (int i = 0; i < n; i++) s.push_back('0');
    for (int i = 1; i < n; i += 2) { s[i] = '1'; add_element(s); s[i] = '0'; }
    for (int j = 1; j < l; j++) {
        for (int i = 0; i < n; i++) s[i] = (i & (1 << (j - 1))) ? '1' : '0';
        for (int i = 0; i < n; i++) {
            if ((i & (1 << j)) == 0) continue;
            s[i] = opp(i);
            add_element(s);
            s[i] = opp(i);
        }
    }
    compile_set();
    fill(s.begin(), s.end(), '0');
    vector <vector <bool>> b(n, vector <bool>(l, false));
    for (int i = 0; i < n; i++) { s[i] = '1'; b[i][0] = check_element(s); s[i] = '0'; }
    for (int j = 1; j < l; j++) {
        for (int i = 0; i < n; i++) s[i] = b[i][j - 1] ? '1' : '0';
        for (int i = 0; i < n; i++) {
            s[i] = opp(i);
            b[i][j] = check_element(s);
            s[i] = opp(i);
        }
    }
    vector <int> ans(n, 0);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < l; j++) {
            if (b[i][j]) ans[i] += (1 << j);
        }
    }
    return ans;
}

Compilation message (stderr)

messy.cpp: In function 'std::vector<int> restore_permutation(int, int, int)':
messy.cpp:13:9: warning: 'l' may be used uninitialized in this function [-Wmaybe-uninitialized]
   13 |     int l; for (int j = 0; j <= 7; j++) if (n & (1 << j)) l = j;
      |         ^

• Subtask 1: 20 / 20
• Subtask 2: 18 / 18
• Subtask 3: 11 / 11
• Subtask 4: 21 / 21
• Subtask 5: 30 / 30