2019年牛客多校第四场 B题xor(线段树+线性基交)
作者:互联网
题目链接
题意
给你\(n\)个基底,求\([l,r]\)内的每个基底是否都能异或出\(x\)。
思路
线性基交板子题,但是一直没看懂咋求,先偷一份咖啡鸡板子写篇博客吧~
线性基交学习博客:传送门
代码实现如下
#include <set>
#include <map>
#include <deque>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <bitset>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <unordered_map>
using namespace std;
typedef unsigned int ui;
typedef long long LL;
typedef pair<LL, LL> pLL;
typedef pair<LL, int> pLi;
typedef pair<int, LL> pil;;
typedef pair<int, int> pii;
typedef unsigned long long uLL;
#define lson rt<<1
#define rson rt<<1|1
#define lowbit(x) x&(-x)
#define name2str(name) (#name)
#define bug printf("*********\n")
#define debug(x) cout<<#x"=["<<x<<"]" <<endl
#define FIN freopen("D://Code//in.txt","r",stdin)
#define IO ios::sync_with_stdio(false),cin.tie(0)
#define fuck(x) cout<<#x" = "<<x<<endl
const double eps = 1e-8;
const int mod = 1000000007;
const int maxn = 50000 + 7;
const double pi = acos ( -1 );
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3fLL;
ui x, a[maxn][35];
int n, q, sz, l, r;
struct base{
ui r[32];
ui f[32];
bool ins(ui x){
for (int i=31;i>=0;i--)
if (x>>i){
if (!r[i]) {r[i]=x;return 1;}
x^=r[i];
if (!x) return 0;
}
return 0;
}
void ins2(ui x){
ui tmp=x;
for (int i=31;i>=0;i--)
if (x>>i){
if (!r[i]) {f[i]=tmp;r[i]=x;return;}
x^=r[i]; tmp^=f[i];
if (!x) return;
}
return;
}
bool find(ui x){
for (int i=31;i>=0;i--)
if (x>>i){
if (!r[i]) return 0;
x^=r[i];
}
return x==0;
}
ui calc(ui x){
ui ret=0;
for (int i=31;i>=0;i--){
if (x>>i){
ret^=f[i];
x^=r[i];
}
}
return ret;
}
void print(){
for (int i=0;i<32;i++)cout<<r[i]<<' ';cout<<endl;
}
void clear(){
for (int i=0;i<32;i++) r[i]=f[i]=0;
}
};
struct node {
int l, r;
base val;
}segtree[maxn<<2];
void push_up(int rt) {
base tmp = segtree[lson].val;
base ans;
ans.clear();
for(int i = 31; i >= 0; --i) {
ui x = segtree[rson].val.r[i];
if(tmp.find(x)) {
ans.ins(x^tmp.calc(x));
} else tmp.ins2(x);
}
segtree[rt].val = ans;
}
void build(int rt, int l, int r) {
segtree[rt].l = l, segtree[rt].r = r;
if(l == r) {
for(int i = 0; i <= 31; ++i) segtree[rt].val.ins(a[l][i]);
return;
}
int mid = (l + r) >> 1;
build(lson, l, mid);
build(rson, mid + 1, r);
push_up(rt);
}
bool query(int rt, int l, int r, LL x) {
if(segtree[rt].l == l && segtree[rt].r == r) {
return segtree[rt].val.find(x);
}
int mid = (segtree[rt].l + segtree[rt].r) >> 1;
if(r <= mid) return query(lson, l, r, x);
else if(l > mid) return query(rson, l, r, x);
else {
return query(lson, l, mid, x) && query(rson, mid + 1, r, x);
}
}
int main() {
#ifndef ONLINE_JUDGE
FIN;
#endif // ONLINE_JUDGE
scanf("%d%d", &n, &q);
for(int i = 1; i <= n; ++i) {
scanf("%d", &sz);
for(int j = 0; j < sz; ++j) scanf("%lld", &a[i][j]);
for(int j = sz; j <= 31; ++j) a[i][j] = 0;
}
build(1, 1, n);
while(q--) {
scanf("%d%d%lld", &l, &r, &x);
if(query(1, l, r, x)) printf("YES\n");
else printf("NO\n");
}
return 0;
}
标签:rt,第四场,基交,segtree,多校,int,ui,return,include 来源: https://www.cnblogs.com/Dillonh/p/11257321.html