Submission #1181357

#	Time	Username	Problem	Language	Result	Execution time	Memory
1181357		nguyn	XORanges (eJOI19_xoranges)	C++20	100 / 100	51 ms	3912 KiB

xoranges

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

#define ll long long 
#define F first
#define S second
#define pb push_back 
#define pii pair<int,int>

const int N = 2e5 + 5;

struct BIT {
	int n; 
	vector<int> bit;

	BIT () {}
	BIT (int n) : n(n) {
		bit.assign(n + 3, 0);
	}

	void update(int id, int val) {
		for (int i = id; i <= n; i += (i & -i)) bit[i] ^= val; 
	}
	
	int get(int id) {
		int res = 0;
		for (int i = id; i; i -= (i & -i)) res ^= bit[i]; 
		return res;
	}

	int get(int l, int r) {
		return get(r) ^ get(l - 1); 
	}
} bit[2]; 

int n, q;
int a[N]; 

signed main(){
    ios_base::sync_with_stdio(false) ; 
    cin.tie(0) ; cout.tie(0) ; 
    if (fopen("INP.INP" ,"r")) {
        freopen("INP.INP" ,"r" , stdin) ;
        freopen("OUT.OUT" , "w" , stdout) ;
    }
    cin >> n >> q;
    bit[0] = BIT(n);
    bit[1] = BIT(n);
    for (int i = 1; i <= n; i++) {
    	cin >> a[i]; 
    	bit[i & 1].update(i, a[i]); 
    }
    while(q--) {
    	int type;
    	cin >> type;
    	if (type == 1) {
    		int i, j;
    		cin >> i >> j;
    		bit[i & 1].update(i, a[i]); 
    		a[i] = j;
    		bit[i & 1].update(i, a[i]); 
    	}
    	if (type == 2) {
    		int l, r; 
    		cin >> l >> r; 
    		if (l & 1) {
	    		if (r & 1) {
	    			cout << bit[1].get(l, r);
	    		}
	    		else {
	    			cout << 0; 
	    		}
    		}
    		else {
    			if (r & 1) {
    				cout << 0;
    			}
    			else {
    				cout << bit[0].get(l, r);
    			}
    		}
    		cout << '\n';
    	}
    }
}

Compilation message (stderr)

xoranges.cpp: In function 'int main()':
xoranges.cpp:43:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |         freopen("INP.INP" ,"r" , stdin) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
xoranges.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen("OUT.OUT" , "w" , stdout) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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