#6009. 「网络流 24 题」软件补丁

https://loj.ac/s/1578956

LibreOJ/6009/6009.cpp

@@ -0,0 +1,90 @@
+#include <iostream>
+#include <algorithm>
+#include <array>
+#include <queue>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 25,
+          M = 105;
+const int INF = 0x3f3f3f3f;
+
+int n, m;
+std::array<int, M> a, b1, b2, f1, f2;
+std::array<int, 1 << N> dist;
+std::array<bool, 1 << N> vis;
+
+bool check(int s, int i) {
+    if ((b1[i] | s) != s) return false;
+    if (b2[i] & s) return false;
+
+    return true;
+}
+
+void spfa(int s) {
+    std::fill(dist.begin(), dist.end(), INF);
+
+    std::queue<int> q;
+    q.push(s);
+    dist[s] = 0;
+    vis[s] = true;
+
+    while (!q.empty()) {
+        int u = q.front();
+        q.pop();
+
+        for (int i = 1; i <= m; i++) {
+            if (!check(u, i)) continue;
+
+            int v = u ^ (u & f1[i]) | f2[i];
+
+            if (dist[u] + a[i] < dist[v]) {
+                dist[v] = dist[u] + a[i];
+
+                if (!vis[v]) {
+                    q.push(v);
+                    vis[v] = true;
+                }
+            }
+        }
+
+        vis[u] = false;
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1; i <= m; i++) {
+        std::string b, f;
+
+        cin >> a[i] >> b >> f;
+
+        for (int j = 0; j < b.size(); j++) {
+            if (b[j] == '+') {
+                b1[i] = b1[i] | 1 << j;
+            } else if (b[j] == '-') {
+                b2[i] = b2[i] | 1 << j;
+            }
+        }
+
+        for (int j = 0; j < f.size(); j++) {
+            if (f[j] == '-') {
+                f1[i] = f1[i] | 1 << j;
+            } else if (f[j] == '+') {
+                f2[i] = f2[i] | 1 << j;
+            }
+        }
+    }
+
+    spfa((1 << n) - 1);
+
+    cout << (dist[0] == INF ? 0 : dist[0]) << endl;
+
+    return 0;
+}