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https://git.sb/baoshuo/OI-codes.git
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119 lines
2.3 KiB
C++
119 lines
2.3 KiB
C++
#include <iostream>
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#include <cstring>
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#include <limits>
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#include <queue>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 205,
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M = 10205;
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int n, m, s, t;
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int idx, head[N], ver[M << 2], next[M << 2];
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std::pair<int, int> edge[M << 2];
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int f[N], d[N], cur[N];
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void add(int u, int v, int a, int b) {
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ver[idx] = v;
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edge[idx] = std::make_pair(a, b);
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next[idx] = head[u];
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head[u] = idx++;
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}
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bool bfs() {
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memset(d, 0x00, sizeof(d));
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std::queue<int> q;
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q.push(s);
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d[s] = 1;
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cur[s] = head[s];
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while (!q.empty()) {
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int u = q.front();
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q.pop();
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for (int i = head[u]; ~i; i = next[i]) {
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int v = ver[i];
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if (!d[v] && edge[i].first) {
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d[v] = d[u] + 1;
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cur[v] = head[v];
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if (v == t) return true;
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q.push(v);
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}
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}
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}
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return false;
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}
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int dinic(int u, int limit) {
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if (u == t) return limit;
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int flow = 0;
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for (int &i = cur[u]; ~i && flow < limit; i = next[i]) {
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int v = ver[i];
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if (d[v] == d[u] + 1 && edge[i].first) {
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int k = dinic(v, std::min(edge[i].first, limit - flow));
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if (!k) d[v] = 0;
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edge[i].first -= k;
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edge[i ^ 1].first += k;
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flow += k;
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}
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}
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return flow;
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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memset(head, 0xff, sizeof(head));
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cin >> n >> m;
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for (int i = 1, u, v, a, b; i <= m; i++) {
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cin >> u >> v >> a >> b;
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add(u, v, b - a, a);
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add(v, u, 0, 0);
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f[u] -= a, f[v] += a;
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}
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int sum = 0;
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s = 0, t = n + 1;
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for (int i = 1; i <= n; i++) {
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if (f[i] > 0) {
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add(s, i, f[i], 0);
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add(i, s, 0, 0);
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sum += f[i];
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} else if (f[i] < 0) {
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add(i, t, -f[i], 0);
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add(t, i, 0, 0);
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}
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}
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int res = 0, flow;
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while (bfs()) {
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while (flow = dinic(s, std::numeric_limits<int>::max())) res += flow;
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}
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if (res == sum) {
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cout << "YES" << endl;
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for (int i = 0; i < m << 1; i += 2) {
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cout << edge[i ^ 1].first + edge[i].second << endl;
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}
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} else {
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cout << "NO" << endl;
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}
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return 0;
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}
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