线段树优化建图+最大流
#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
#define mem(s, v) memset(s, v, sizeof s)
#define FILEIN(s) freopen(s".in", "r", stdin)
#define FILEOUT(s) freopen(s".out", "w", stdout)
inline int read(void) {
int x = 0, f = 1; char ch = getchar();
while (ch < '0' || ch > '9') { if (ch == '-') f = -1; ch = getchar(); }
while (ch >= '0' && ch <= '9') { x = x * 10 + ch - '0'; ch = getchar(); }
return f * x;
}
const int maxk = 100005, maxm = 20005, inf = 1e8;
const int maxv = maxk * 4 + maxm, maxe = maxk * 1 + maxk * 4 + maxm * 18 * 2;
int n, m, K;
int head[maxv], tot = 1, sz;
int rt[2], S, T;
int son[maxk << 2][2], L[maxk << 2], R[maxk << 2];
int cur[maxv], d[maxv];
int pos[2][maxk];
struct Edge {
int y, next, w;
Edge() {}
Edge(int _y, int _next, int _w) : y(_y), next(_next), w(_w) {}
}e[maxe << 1];
inline void connect(int x, int y, int w) {
e[++tot] = Edge(y, head[x], w);
head[x] = tot;
}
inline void add(int x, int y, int w) {
connect(x, y, w); connect(y, x, 0);
}
inline int New() { ++sz; return sz; }
void build(int o, int l, int r, bool k) {
L[o] = l; R[o] = r;
if (l == r) {
pos[k][l] = o;
return;
}
son[o][0] = New(); son[o][1] = New();
int mid = (l + r) >> 1;
build(son[o][0], l, mid, k);
build(son[o][1], mid + 1, r, k);
if (!k) add(son[o][0], o, inf), add(son[o][1], o, inf);
else add(o, son[o][0], inf), add(o, son[o][1], inf);
}
void link(int o, int ql, int qr, int t, int l, bool k) {
if (ql <= L[o] && R[o] <= qr) {
if (!k) add(o, t, l);
else add(t, o, l);
return;
}
int mid = (L[o] + R[o]) >> 1;
if (ql <= mid) link(son[o][0], ql, qr, t, l, k);
if (qr > mid) link(son[o][1], ql, qr, t, l, k);
}
bool bfs(void) {
queue<int>q;
cur[S] = head[S];
q.push(S);
mem(d, -1); d[S] = 1;
while (q.size()) {
int x = q.front(); q.pop();
for (int i = head[x]; i; i = e[i].next) {
int y = e[i].y;
if (e[i].w && d[y] == -1) {
d[y] = d[x] + 1;
cur[y] = head[y];
if (y == T) return true;
q.push(y);
}
}
}
return false;
}
int find(int x, int limit) {
if (x == T) return limit;
int flow = 0;
for (int i = cur[x]; i && flow < limit; i = e[i].next) {
cur[x] = i;
int y = e[i].y;
if (e[i].w && d[y] == d[x] + 1) {
int t = find(y, min(e[i].w, limit - flow));
if (!t) d[y] = -1;
flow += t;
e[i].w -= t;
e[i ^ 1].w += t;
}
}
return flow;
}
inline void dinic(void) {
int r = 0, flow;
while (bfs()) while (flow = find(S, inf)) r += flow;
printf("%d\n", min(r, n));
}
int main() {
n = read(); m = read(); K = read();
rt[0] = New();
build(rt[0], 1, K, 0);
rt[1] = New();
build(rt[1], 1, K, 1);
for (int i = 1; i <= K; ++i) //add(pos[1][i], pos[0][i], inf);
connect(pos[0][i], pos[1][i], inf),
connect(pos[1][i], pos[0][i], inf);
S = New(); T = New();
add(S, pos[0][1], inf); add(pos[1][K], T, inf);
while (m--) {
int opt = read(), limit = read();
if (opt == 1) {
int a = read(), b = read();
add(pos[0][a], pos[1][b], limit);
}
else if (opt == 2) {
int l = read(), r = read(), b = read();
link(rt[0], l, r, pos[1][b], limit, 0);
}
else if (opt == 3) {
int a = read(), l = read(), r = read();
link(rt[1], l, r, a, limit, 1);
}
else if (opt == 4) {
int l1 = read(), r1 = read(), l2 = read(), r2 = read(), x = New();
link(rt[0], l1, r1, x, limit, 0);
link(rt[1], l2, r2, x, limit, 1);
}
}
dinic();
return 0;
}
出题人您能提供一下倒数第二个点的数据吗?
@Wen_kr