제출 #1354655

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1354655		vjudge1	XOR (IZhO12_xor)	C++17	100 / 100	88 ms	25068 KiB

xor

#include<bits/stdc++.h>
#define ll long long
using namespace std;

const int INF = 1e18;
const int M = 29;

struct Node
{
    int child[2], mn;
    Node()
    {
        child[0] = child[1] = -1;
        mn = INF;
    }
};

vector<Node> trie;

void add(int val, int id)
{
    int u = 0;
    trie[u].mn = min(trie[u].mn, id);
    for(int i = M; i >= 0; i--)
    {
        int bit = (val >> i) & 1;
        if(trie[u].child[bit] == -1)
        {
            trie[u].child[bit] = trie.size();
            trie.push_back(Node());
        }
        u = trie[u].child[bit];
        trie[u].mn = min(trie[u].mn, id);
    }
}

int get(int val, int x)
{
    int u = 0;
    int res = INF;
    for(int i = M; i >= 0; i--)
    {
        if(u == -1) return res;
        int b1 = (val >> i) & 1;
        int b2 = (x >> i) & 1;
        if(b2 == 0)
        {
            int nxt = 1 - b1;
            if(trie[u].child[nxt] != -1)
                res = min(res, trie[trie[u].child[nxt]].mn);
            u = trie[u].child[b1];
        }
        else    u = trie[u].child[1 - b1];
    }
    if(u != -1) res = min(res, trie[u].mn);
    return res;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);     cout.tie(0);
    #define name "task"
    if(fopen(name".inp", "r"))
    {
        freopen(name".inp", "r", stdin);
        freopen(name".out", "w", stdout);
    }
    int n, x;
    cin >> n >> x;
    trie.push_back(Node());
    add(0, 0);
    int px = 0;
    int st = -1, len = -1;
    for(int i = 1; i <= n; i++)
    {
        int a;
        cin >> a;
        px ^= a;
        int pos = get(px, x);
        if(pos != INF)
        {
            int cur = i - pos;
            if(cur > len)
            {
                len = cur;
                st = pos + 1;
            }
            else if(cur == len)    st = min(st, pos + 1);
        }
        add(px, i);
    }
    if(st != -1) cout << st << ' ' << len;
}

컴파일 시 표준 에러 (stderr) 메시지

xor.cpp:5:17: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
    5 | const int INF = 1e18;
      |                 ^~~~
xor.cpp: In function 'int main()':
xor.cpp:66:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |         freopen(name".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
xor.cpp:67:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |         freopen(name".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100