Submission #30833

#	Time	Username	Problem	Language	Result	Execution time	Memory
30833		Kerim	XOR (IZhO12_xor)	C++14	100 / 100	276 ms	90888 KiB

xor

#include "bits/stdc++.h"
#define MAXN 250009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x)  cerr<< #x <<" = "<< x<<endl;
using namespace std;

typedef long long ll;
typedef pair<int,int> PII;
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
const int LOGN=30;
int par[MAXN],tree[MAXN*LOGN][2],node,sub[MAXN*LOGN],n,k;
void upd(int x){
	int now=0;
	for(int i=29;i>=0;i--){
		int bit=par[x]>>i&1;
		if(!tree[now][bit])
			tree[now][bit]=++node;
		now=tree[now][bit];
		umax(sub[now],x);	
	}
}
int get(int x){
	int now=0,val=0,res=0;
	for(int i=29;i>=0;i--){
		int bit=x>>i&1;
		int v1=tree[now][bit^1];
		int v0=tree[now][bit];
		if(v0 and v1){
			if(val+(1<<i)>=k)
				umax(res,sub[v1]),now=v0;
			else
				val+=(1<<i),now=v1;
		}
		else if(v1){
			if(val+(1<<i)>=k)
				umax(res,sub[v1]);
			else
				val+=(1<<i);
			now=v1;
		}
		else
			now=v0;
	}
	return res;
}
int main(){
	//~ #ifndef ONLINE_JUDGE
    //~ freopen("file.in", "r", stdin);
	//~ #endif	
	scanf("%d%d",&n,&k);
	for(int i=1;i<=n;i++){
		int x;
		scanf("%d",&x);
		par[i]=par[i-1]^x;
	}int ans,mx=0;
	for(int i=n;i>=1;i--){
		upd(i);int res=get(par[i-1]);
		if(res and res-i+1>=mx)
			mx=res-i+1,ans=i;
	}
	printf("%d %d\n",ans,mx);
	return 0;
}

Compilation message (stderr)

xor.cpp: In function 'int main()':
xor.cpp:60:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&k);
                     ^
xor.cpp:63:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&x);
                 ^

• Subtask 1: 100 / 100