Luogu 4899 [IOI2018] werewolf 狼人
作者：互联网
UOJ 407
kruskal重构树
所有边的边权记为两个点的$max$建立一棵重构树，这样子可以做出一个点走不超过$R$能到达的点的集合，再把所有边的边权记为两个点的$min$建立重构树，这样子可以做出一个点走不少于$L$所能到达的点的集合
注意到这两个集合其实是重构树叶子的一段区间，问题有解等价于区间有交，这样子就变成了一个二维数点问题
暴力线段树合并过不去，别问我是怎么知道的
一开始交的时候边数开错了
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include "werewolf.h"
using namespace std;
const int N = 8e5 + 5;
const int M = 2e5 + 5;
const int Lg = 22;
const int inf = 1 << 30;
int n, m, qn, tot = 0, head[N], ufs[N];
int rt1, rt2, ncnt, w[N], fa[N][Lg];
int ln[N], rn[N], dfsc = 0, id1[M], id2[M], px1[M], px2[M], ans[M];
struct Edge {
int to, nxt;
} e[N];
inline void add(int from, int to) {
e[++tot].to = to;
e[tot].nxt = head[from];
head[from] = tot;
}
struct Path {
int u, v, val;
friend bool operator < (const Path x, const Path y) {
return x.val < y.val;
}
} pat[M << 1];
struct Query {
int s, t, lv, rv;
} q[M];
struct Seg {
int l, r, id, type;
};
vector <Seg> vec[M];
namespace Fread {
const int L = 1 << 15;
char buffer[L], *S, *T;
inline char Getchar() {
if(S == T) {
T = (S = buffer) + fread(buffer, 1, L, stdin);
if(S == T) return EOF;
}
return *S++;
}
template <class T>
inline void read(T &X) {
char ch; T op = 1;
for(ch = Getchar(); ch > '9' || ch < '0'; ch = Getchar())
if(ch == '-') op = -1;
for(X = 0; ch >= '0' && ch <= '9'; ch = Getchar())
X = (X << 1) + (X << 3) + ch - '0';
X *= op;
}
} using Fread :: read;
namespace Fwrite {
const int L = 1 << 15;
char buf[L], *pp = buf;
void Putchar(const char c) {
if(pp - buf == L) fwrite(buf, 1, L, stdout), pp = buf;
*pp++ = c;
}
template<typename T>
void print(T x) {
if(x < 0) {
Putchar('-');
x = -x;
}
if(x > 9) print(x / 10);
Putchar(x % 10 + '0');
}
void fsh() {
fwrite(buf, 1, pp - buf, stdout);
pp = buf;
}
template <typename T>
inline void write(T x, char ch = 0) {
print(x);
if (ch != 0) Putchar(ch);
}
} using Fwrite :: write;
/*
namespace SegT {
struct Node {
int lc, rc, sum;
} s[N * 20];
int root[N], pcnt = 0, top = 0, pool[N * 20];
#define lc(p) s[p].lc
#define rc(p) s[p].rc
#define sum(p) s[p].sum
#define mid ((l + r) >> 1)
inline void up(int p) {
if (!p) return;
sum(p) = sum(lc(p)) + sum(rc(p));
}
inline int newNode() {
if (top) return pool[top--];
else return ++pcnt;
}
inline void del(int p) {
pool[++top] = p;
}
int merge(int u, int v, int l, int r) {
if (!u || !v) return u + v;
int p = newNode();
if (l == r) {
sum(p) = sum(u) + sum(v);
} else {
lc(p) = merge(lc(u), lc(v), l, mid);
rc(p) = merge(rc(u), rc(v), mid + 1, r);
up(p);
}
del(u), del(v);
return p;
}
void build(int &p, int l, int r, int x) {
if (!p) p = newNode();
if (l == r) {
++sum(p);
return;
}
if (x <= mid) build(lc(p), l, mid, x);
else build(rc(p), mid + 1, r, x);
up(p);
}
int query(int p, int l, int r, int x, int y) {
if (!p) return 0;
if (x <= l && y >= r) return sum(p);
int res = 0;
if (x <= mid) res += query(lc(p), l, mid, x, y);
if (y > mid) res += query(rc(p), mid + 1, r, x, y);
up(p);
return res;
}
void print(int k) {
printf("%d : ", k);
for (int i = 1; i <= n; i++)
printf("%d ", query(root[k], 1, n, i, i));
puts("");
}
#undef mid
} using namespace SegT; */
int find(int x) {
return ufs[x] == x ? x : ufs[x] = find(ufs[x]);
}
void dfs1(int x, int fat) {
bool isLeaf = 1;
ln[x] = inf, rn[x] = -inf;
fa[x][0] = fat;
for (int i = 1; i <= 20; i++) fa[x][i] = fa[fa[x][i - 1]][i - 1];
for (int i = head[x]; i; i = e[i].nxt) {
int y = e[i].to;
isLeaf = 0;
dfs1(y, x);
ln[x] = min(ln[x], ln[y]);
rn[x] = max(rn[x], rn[y]);
}
if (isLeaf) {
id1[++dfsc] = x;
px1[x] = dfsc;
ln[x] = rn[x] = dfsc;
}
}
void dfs2(int x, int fat) {
bool isLeaf = 1;
ln[x] = inf, rn[x] = -inf;
fa[x][0] = fat;
for (int i = 1; i <= 20; i++) fa[x][i] = fa[fa[x][i - 1]][i - 1];
for (int i = head[x]; i; i = e[i].nxt) {
int y = e[i].to;
isLeaf = 0;
dfs2(y, x);
ln[x] = min(ln[x], ln[y]);
rn[x] = max(rn[x], rn[y]);
}
if (isLeaf) {
id2[++dfsc] = x - 2 * n;
px2[x - 2 * n] = dfsc;
ln[x] = rn[x] = dfsc;
}
}
inline int getPos1(int x, int val) {
w[0] = inf;
for (int i = 20; i >= 0; i--)
if (w[fa[x][i]] <= val) x = fa[x][i];
return x;
}
inline int getPos2(int x, int val) {
w[0] = 0;
for (int i = 20; i >= 0; i--)
if (w[fa[x][i]] >= val) x = fa[x][i];
return x;
}
/* void solve(int x, int fat) {
stk[++tp] = x;
for (int i = head[x]; i; i = e[i].nxt) {
int y = e[i].to;
solve(y, x);
root[x] = merge(root[x], root[y], 1, n);
}
int siz = vec[x].size();
for (int i = 0; i < siz; i++) {
int qid = vec[x][i];
int pos = getPos2(q[qid].s + 2 * n, q[qid].lv);
// printf("%d %d\n", qid, pos);
ans[qid] = query(root[x], 1, n, ln[pos - 2 * n], rn[pos - 2 * n]);
}
// print(x);
--tp;
} */
void debug(int x, int fat, bool is2 = 0) {
printf("%d:%d\n", x, w[x]);
if (is2) printf("%d::%d %d\n", x, ln[x - 2 * n], rn[x - 2 * n]);
for (int i = head[x]; i; i = e[i].nxt) {
int y = e[i].to;
printf("%d %d\n", x, y);
debug(y, x);
}
}
namespace Bit {
int s[M];
#define lowbit(p) (p & (-p))
inline void modify(int p) {
for (; p <= n; p += lowbit(p)) ++s[p];
}
inline int query(int p) {
int res = 0;
for (; p > 0; p -= lowbit(p)) res += s[p];
return res;
}
} using namespace Bit;
/*int main() {
#ifndef ONLINE_JUDGE
freopen("sample.in", "r", stdin);
freopen("my.out", "w", stdout);
#endif
read(n), read(m), read(qn);
for (int i = 1; i <= m; i++) {
read(pat[i].u), read(pat[i].v);
++pat[i].u, ++pat[i].v;
pat[i].val = max(pat[i].u, pat[i].v);
}
for (int i = 1; i <= 4 * n; i++) ufs[i] = i;
ncnt = n;
sort(pat + 1, pat + 1 + m);
for (int cnt = 0, i = 1; i <= m; i++) {
int u = pat[i].u, v = pat[i].v;
int fu = find(u), fv = find(v);
if (fu == fv) continue;
++cnt, ++ncnt;
w[ncnt] = pat[i].val;
ufs[fu] = ufs[fv] = ncnt;
add(ncnt, fu), add(ncnt, fv);
if (cnt == n - 1) break;
}
rt1 = find(1), dfsc = 0;
dfs1(rt1, 0);
// debug(rt1, 0);
for (int i = 1; i <= m; i++) pat[i].val = min(pat[i].u, pat[i].v);
ncnt = 3 * n;
sort(pat + 1, pat + 1 + m);
for (int cnt = 0, i = m; i >= 1; i--) {
int u = pat[i].u + 2 * n, v = pat[i].v + 2 * n;
int fu = find(u), fv = find(v);
if (fu == fv) continue;
++cnt, ++ncnt;
w[ncnt] = pat[i].val;
ufs[fu] = ufs[fv] = ncnt;
add(ncnt, fu), add(ncnt, fv);
if (cnt == n - 1) break;
}
rt2 = find(2 * n + 1), dfsc = 0;
dfs2(rt2, 0);
// puts("");
// debug(rt2, 0, 1);
// for (int i = 1; i <= n; i++)
// printf("%d%c", id[i], " \n"[i == n]);
// for (int i = 1; i <= n; i++)
// printf("%d ", id1[i]);
// printf("\n");
// for (int i = 1; i <= n; i++)
// printf("%d ", id2[i]);
// printf("\n");
// for (int i = 1; i <= n; i++)
// printf("%d ", px2[id1[i]]);
// printf("\n");
for (int i = 1; i <= qn; i++) {
read(q[i].s), read(q[i].t), read(q[i].lv), read(q[i].rv);
++q[i].s, ++q[i].t, ++q[i].lv, ++q[i].rv;
int pos1 = getPos1(q[i].t, q[i].rv), pos2 = getPos2(q[i].s + 2 * n, q[i].lv);
// printf("%d %d %d %d\n", ln[pos1], rn[pos1], ln[pos2], rn[pos2]);
vec[ln[pos1] - 1].push_back((Seg) {ln[pos2], rn[pos2], i, -1});
vec[rn[pos1]].push_back((Seg) {ln[pos2], rn[pos2], i, 1});
}
for (int i = 1; i <= n; i++) {
int siz = vec[i].size();
modify(px2[id1[i]]);
for (int j = 0; j < siz; j++) {
int l = vec[i][j].l, r = vec[i][j].r, t = vec[i][j].type, qid = vec[i][j].id;
ans[qid] += t * (query(r) - query(l - 1));
}
}
// for (int i = 1; i <= qn; i++)
// write(ans[i] > 0 ? 1 : 0, '\n');
for (int i = 1; i <= qn; i++)
write(ans[i] > 0 ? 1 : 0, '\n');
Fwrite :: fsh();
return 0;
} */
vector<int> check_validity(int N, vector<int> X, vector<int> Y, vector<int> S, vector<int> E, vector<int> L, vector<int> R) {
// read(n), read(m), read(qn);
n = N, m = X.size(), qn = S.size();
for (int i = 1; i <= m; i++) {
// read(pat[i].u), read(pat[i].v);
pat[i].u = X[i - 1], pat[i].v = Y[i - 1];
++pat[i].u, ++pat[i].v;
pat[i].val = max(pat[i].u, pat[i].v);
}
for (int i = 1; i <= 4 * n; i++) ufs[i] = i;
ncnt = n;
sort(pat + 1, pat + 1 + m);
for (int cnt = 0, i = 1; i <= m; i++) {
int u = pat[i].u, v = pat[i].v;
int fu = find(u), fv = find(v);
if (fu == fv) continue;
++cnt, ++ncnt;
w[ncnt] = pat[i].val;
ufs[fu] = ufs[fv] = ncnt;
add(ncnt, fu), add(ncnt, fv);
if (cnt == n - 1) break;
}
rt1 = find(1), dfsc = 0;
dfs1(rt1, 0);
// debug(rt1, 0);
for (int i = 1; i <= m; i++) pat[i].val = min(pat[i].u, pat[i].v);
ncnt = 3 * n;
sort(pat + 1, pat + 1 + m);
for (int cnt = 0, i = m; i >= 1; i--) {
int u = pat[i].u + 2 * n, v = pat[i].v + 2 * n;
int fu = find(u), fv = find(v);
if (fu == fv) continue;
++cnt, ++ncnt;
w[ncnt] = pat[i].val;
ufs[fu] = ufs[fv] = ncnt;
add(ncnt, fu), add(ncnt, fv);
if (cnt == n - 1) break;
}
rt2 = find(2 * n + 1), dfsc = 0;
dfs2(rt2, 0);
// puts("");
// debug(rt2, 0, 1);
// for (int i = 1; i <= n; i++)
// printf("%d%c", id[i], " \n"[i == n]);
// for (int i = 1; i <= n; i++)
// printf("%d ", id1[i]);
// printf("\n");
// for (int i = 1; i <= n; i++)
// printf("%d ", id2[i]);
// printf("\n");
// for (int i = 1; i <= n; i++)
// printf("%d ", px2[id1[i]]);
// printf("\n");
for (int i = 1; i <= qn; i++) {
// read(q[i].s), read(q[i].t), read(q[i].lv), read(q[i].rv);
q[i].s = S[i - 1], q[i].t = E[i - 1], q[i].lv = L[i - 1], q[i].rv = R[i - 1];
++q[i].s, ++q[i].t, ++q[i].lv, ++q[i].rv;
int pos1 = getPos1(q[i].t, q[i].rv), pos2 = getPos2(q[i].s + 2 * n, q[i].lv);
// printf("%d %d %d %d\n", ln[pos1], rn[pos1], ln[pos2], rn[pos2]);
vec[ln[pos1] - 1].push_back((Seg) {ln[pos2], rn[pos2], i, -1});
vec[rn[pos1]].push_back((Seg) {ln[pos2], rn[pos2], i, 1});
}
for (int i = 1; i <= n; i++) {
int siz = vec[i].size();
modify(px2[id1[i]]);
for (int j = 0; j < siz; j++) {
int l = vec[i][j].l, r = vec[i][j].r, t = vec[i][j].type, qid = vec[i][j].id;
ans[qid] += t * (query(r) - query(l - 1));
}
}
// for (int i = 1; i <= qn; i++)
// write(ans[i] > 0 ? 1 : 0, '\n');
// for (int i = 1; i <= qn; i++)
// write(ans[i] > 0 ? 1 : 0, '\n');
// Fwrite :: fsh();
vector <int> retAns;
for (int i = 1; i <= qn; i++) retAns.push_back(ans[i] > 0 ? 1 : 0);
return retAns;
}
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标签：4899,ch,return,int,Luogu,void,狼人,ncnt,sum 来源： https://www.cnblogs.com/CzxingcHen/p/13852597.html