Submission #255991

#	Time	Username	Problem	Language	Result	Execution time	Memory
255991		tomsyd	XORanges (eJOI19_xoranges)	C++17	100 / 100	190 ms	16416 KiB

xoranges

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

const int N = 2e5+1;
vector<int> a(N);

void build(int idx, int l, int r, vector<int>& segt, int rest){
	if (l == r){
		if (l%2 == rest) segt[idx] = a[l];
		return;
	}
	int mid = (l+r)>>1;
	build(2*idx,l,mid,segt,rest);
	build(2*idx+1,mid+1,r,segt,rest);
	segt[idx] = segt[2*idx]^segt[2*idx+1];
}

void modify(int idx, int l, int r, int pos, int val, vector<int>& segt){
	if (r < pos or l > pos) return;
	if (l == r){
		segt[idx] = val;
		return;
	}
	int mid = (l+r)>>1;
	modify(2*idx,l,mid,pos,val,segt);
	modify(2*idx+1,mid+1,r,pos,val,segt);
	segt[idx] = segt[2*idx]^segt[2*idx+1];
}

int query(int idx, int l, int r, int L, int R, vector<int>& segt){
	if (r < L or l > R) return 0;
	if (l >= L and r <= R) return segt[idx];
	int mid = (l+r)>>1;
	return query(2*idx,l,mid,L,R,segt)^query(2*idx+1,mid+1,r,L,R,segt);
}

int32_t main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int n,q;
	cin >> n >> q;
	vector<int> odd(4*N+5), even(4*N+5);
	for (int i=0; i<n; ++i){
		cin >> a[i];
	}
	build(1,0,n-1,even,0);
	build(1,0,n-1,odd,1);
	for (int i=0; i<q; ++i){
		int type;
		cin >> type;
		if (type == 1){
			int pos, val;
			cin >> pos >> val;
			pos--;
			if (pos%2 == 0) modify(1,0,n-1,pos,val,even);
			else modify(1,0,n-1,pos,val,odd);
		}
		else{
			int l,r;
			cin >> l >> r;
			l--; r--;
			int ans = 0;
			if ((r-l+1)%2 == 0){
				cout << 0 << '\n';
				continue;
				if (l%2 == 0) ans = query(1,0,n-1,l,r,odd);
				else ans = query(1,0,n-1,l,r,even);
			}
			else{
				if (l%2 == 0) ans = query(1,0,n-1,l,r,even);
				else ans = query(1,0,n-1,l,r,odd);
			}
			cout << ans << '\n';
		}
	}
	return 0;
}

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 25 / 25
• Subtask 4: 20 / 20
• Subtask 5: 25 / 25