Submission #675660

#	Time	Username	Problem	Language	Result	Execution time	Memory
675660		Alma	XORanges (eJOI19_xoranges)	C++17	0 / 100	535 ms	9008 KiB

xoranges

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

int n, m, q;
vector<int> a, values;
vector<int> segTree;

void build(int x, int l, int r) {
    if (l == r) {
        segTree[x] = values[l];
        return;
    }
    int mid = (l+r)/2;
    build(2*x, l, mid);
    build(2*x+1, mid+1, r);
    segTree[x] = segTree[2*x] ^ segTree[2*x+1];
}

void update(int x, int l, int r, int i, int v) {
    if (l == r) {
        segTree[x] = values[l] = v;
        return;
    }
    int mid = (l+r)/2;
    if (i <= mid) {
        update(2*x, l, mid, i, v);
    } else{
        update(2*x+1, mid+1, r, i, v);
    }
    segTree[x] = segTree[2*x] ^ segTree[2*x+1];
}

int getRange(int x, int l, int r, int lb, int rb) {
    if (rb <= l or r <= lb) {
        return 0;
    } else if (lb <= l and r <= rb) {
        return segTree[x];
    } else {
        int mid = (l+r)/2;
        int xor1 = getRange(2*x, l, mid, lb, rb);
        int xor2 = getRange(2*x+1, mid+1, r, lb, rb);
        return xor1 ^ xor2;
    }
}

int main() {
    // ios::sync_with_stdio(false);
    // cin.tie(NULL);
    
    cin >> n >> q;
    a = vector<int>(n);
    for (int& i: a) cin >> i;

    m = (n+1)/2;
    values = vector<int>(m);
    for (int i = 0; i < m; i++) {
        values[i] = a[2*i];
    }
    
    segTree = vector<int>(4*m, 0);
    build(1, 0, m-1);
    // cout << "ok\n";

    int type, i, val, l, r;
    while (q--) {
        cin >> type;
        if (type == 1) { // rescan
            cin >> i >> val;
            a[i-1] = val;
            if (i % 2 == 1) {
                i /= 2;
                update(1, 0, m-1, i, val);
            }
        } else { // query
            cin >> l >> r;
            int range = r-l+1;
            if (l == r) {
                cout << a[l-1] << '\n';
            } else if (range % 2 == 0) {
                cout << "0\n";
            } else {
                l /= 2;
                r /= 2;
                cout << getRange(1, 0, m-1, l, r) << '\n';
            }
        }
    }

    return 0;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 18
• Subtask 3: 0 / 25
• Subtask 4: 0 / 20
• Subtask 5: 0 / 25