oj.uz

Submission #883637

# Submission time Handle Problem Language Result Execution time Memory
883637 2023-12-05T14:49:42 Z Requiem XOR (IZhO12_xor) C++17
0 / 100
 2000 ms 115928 KB 
#include<iostream>
#include<algorithm>
#include<cstring>
#include<vector>
#define pb push_back
#define fast ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#define MOD 1000000007
#define INF 2147483646
#define endl "\n"
#define TASKNAME "Xor"
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
using namespace std;
typedef pair<int,int> ii;
typedef pair<int,ii> iii;
typedef vector<int> vi;
const int MAXN = 250009;
const int block = 501;
int n,k;
int a[MAXN],prexor[MAXN];
struct TrieNode{
    int child[2];
    TrieNode(){
       memset(child,0,sizeof(child));
    }
};
struct Trie{
    vector<TrieNode> Trie = {TrieNode(),TrieNode()};
    int bitpre, bit, it, p, pw2;
    void addnum(int x){
        p = 1;
        for(it=29;it>=0;it--){
            bit = (x>>it)&1;
            if (Trie[p].child[bit] == 0){
                Trie[p].child[bit] = Trie.size();
                Trie.pb(TrieNode());
            }
            p = Trie[p].child[bit];
        }
    }
    inline bool check(int pre,int x){
        p = 1;
        for(it=29;it>=0;it--){
            bitpre = (pre>>it)&1;
            pw2 = (1LL<<it);
            if (Trie[p].child[!bitpre]){
                if (x >= pw2 * 2) return false;
                x -= pw2;
                if (x <= 0) return true;

                p = Trie[p].child[!bitpre];
            }
            else{
                p = Trie[p].child[bitpre];
            }
        }
        return (x <= 0);
    }
};
Trie TrieBlock[2003];
int starting[MAXN],ending[MAXN];
int maxlen, minpos,x;
void update(int node,int l,int r,int pos,int pre){
    TrieBlock[node].addnum(pre);
    if (l==r) return;
    int mid = (l+r)>>1;
    if (pos <= mid) update(node<<1,l,mid,pos,pre);
    else update(node<<1|1,mid+1,r,pos,pre);
}
int getminblock(int node,int l,int r,int u,int v,int pre){
    int mid = (l+r)>>1;
    if (l>=u and r<=v){
        if (l==r) return l;
        if (TrieBlock[node<<1].check(pre,x)){
            return getminblock(node<<1,l,mid,u,v,pre);
        }
        else if (TrieBlock[node<<1|1].check(pre,x)){
            return getminblock(node<<1|1,mid+1,r,u,v,pre);
        }
        else return INF;
    }
    if (l>v or r<u) return INF;
    int g1 = getminblock(node<<1,l,mid,u,v,pre);
    if (g1 != INF) return g1;
    else return getminblock(node<<1|1,mid+1,r,u,v,pre);
}
main()
{
    fast;
   if (fopen(TASKNAME".inp","r")){
        freopen(TASKNAME".inp","r",stdin);
        freopen(TASKNAME".out","w",stdout);
   }
   cin>>n>>x;
   for(int i=1;i<=n;i++){
       cin>>a[i];
       prexor[i] = prexor[i-1] ^ a[i];
   }
   for(int i=0;i<n;i++){
       starting[i/block] = (starting[i/block] == -1) ? i : starting[i/block];
       ending[i/block] = i;
   }
   for(int i=0;i<=2000;i++){
       TrieBlock[i].addnum(0);
   }
   int MXBLOCK = (n-1) / block;
   int minblock = 0, idblock;
   for(int i=0;i<=n;i++){
       idblock = i / block;
       minblock = getminblock(1,0,MXBLOCK,0,idblock,prexor[i]);
       if (minblock != INF){
           for(int j=starting[minblock]; i - j >= maxlen and j<=min(i,ending[minblock]);j++){
                if ((prexor[i] ^ prexor[j]) >= x){
                   if (maximize(maxlen,i - j)){
                       minpos = j + 1;
                       break;
                   }
                   else if (maxlen == i - j){
                       minimize(minpos, j + 1);
                       break;
                   }
               }
           }
       }
       update(1,0,MXBLOCK,idblock,prexor[i]);
   }
   cout<<minpos<<' '<<maxlen<<endl;
}

Compilation message

xor.cpp:87:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   87 | main()
      | ^~~~
xor.cpp: In function 'int main()':
xor.cpp:91:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |         freopen(TASKNAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
xor.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen(TASKNAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2904 KB Output is correct
2 Correct 1 ms 2908 KB Output is correct
3 Correct 1 ms 2908 KB Output is correct
4 Correct 2 ms 3164 KB Output is correct
5 Correct 94 ms 9348 KB Output is correct
6 Correct 169 ms 11140 KB Output is correct
7 Correct 183 ms 11452 KB Output is correct
8 Correct 228 ms 12620 KB Output is correct
9 Correct 1453 ms 104432 KB Output is correct
10 Correct 1390 ms 107656 KB Output is correct
11 Correct 1485 ms 103696 KB Output is correct
12 Correct 1473 ms 108400 KB Output is correct
13 Correct 1413 ms 106340 KB Output is correct
14 Correct 1389 ms 106276 KB Output is correct
15 Correct 1420 ms 110164 KB Output is correct
16 Correct 1438 ms 109808 KB Output is correct
17 Execution timed out 2029 ms 115928 KB Time limit exceeded
18 Halted 0 ms 0 KB -