Submission #963298

#	Time	Username	Problem	Language	Result	Execution time	Memory
963298		Acanikolic	XOR (IZhO12_xor)	C++14	Compilation error	0 ms	0 KiB

xor

#include <bits/stdc++.h>
		 		
//#define int long long 
		 
#define pb push_back 
		
#define F first
		 
#define S second
		 
using namespace std;
		 
const int N = 250010;
		 
const int mod = 1e9 + 7;
		 
const int inf = 1e9;

int pref[N],a[N],trie[N * 31][2],mn[N * 31 * 2],index = 0;

void Add(int x,int i) {
	int node = 0;
	for(int j = 30; j >= 0; j--) {
		int bit = x >> j & 1;
		if(!trie[node][bit]) trie[node][bit] = ++index;
		node = trie[node][bit];
		mn[node] = min(mn[node],i);
	}
}

int get(int tr,int x) {
	int node = 0,val = 0,res = inf;
	for(int j = 30; j >= 0; j--) {
		int bit = x >> j & 1;
		int bt = tr >> j & 1;
		if(bit > 0) {
			if(!trie[node][bit ^ bt]) break;
			node = trie[node][bit ^ bt];
			res = min(res,mn[node]);
		}else {
			if(trie[node][1] > 0) res = min(res,mn[trie[node][1]]);
			if(!trie[node][0]) break;
			node = trie[node][0];
			//if(!j) res = min(res,mn[node]);
		}
	}
	return res;
}
		 		 	 		 
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
	
	int n,x;
	cin >> n >> x;
	for(int i = 1; i < N * 31 * 2; i++) mn[i] = inf;
	int l = n + 1,r = n;
	for(int i = 1; i <= n; i++) {
		cin >> a[i];
		pref[i] = a[i] ^ pref[i - 1];
		if(pref[i] >= x) {
			l = 1,r = i;
		}
		int L = get(pref[i],x);
		if(i - L + 1 > r - l + 1) {
			l = L;
			r = i;
		}
		if(i > 1) Add(pref[i - 1],i);
	}
	cout << l << " " << r - l + 1;
    return 0;
}

Compilation message (stderr)

xor.cpp:19:49: error: 'int index' redeclared as different kind of entity
   19 | int pref[N],a[N],trie[N * 31][2],mn[N * 31 * 2],index = 0;
      |                                                 ^~~~~
In file included from /usr/include/string.h:432,
                 from /usr/include/c++/10/cstring:42,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:48,
                 from xor.cpp:1:
/usr/include/strings.h:61:1: note: previous declaration 'const char* index(const char*, int)'
   61 | index (const char *__s, int __c) __THROW
      | ^~~~~
xor.cpp: In function 'void Add(int, int)':
xor.cpp:25:44: error: no pre-increment operator for type
   25 |   if(!trie[node][bit]) trie[node][bit] = ++index;
      |                                            ^~~~~
xor.cpp: In function 'int get(int, int)':
xor.cpp:32:15: warning: unused variable 'val' [-Wunused-variable]
   32 |  int node = 0,val = 0,res = inf;
      |               ^~~