P3275 [SCOI2011]糖果

R53241911

Luogu/problem/P3275/P3275.cpp

@@ -0,0 +1,72 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, m, x, a, b, head[300005], vis[300005], used[300005], dis[300005], num;
+queue<int> q;
+
+struct {
+    int next, to, val;
+} g[1000005];
+
+void add(int u, int v, int w) {
+    g[++num].next = head[u];
+    g[num].to = v;
+    g[num].val = w;
+    head[u] = num;
+}
+
+int main() {
+    cin >> n >> m;
+    for (int i = 1; i <= m; i++) {
+        cin >> x >> a >> b;
+        if (x == 1) {
+            add(a, b, 0);
+            add(b, a, 0);
+        } else if (x == 2) {
+            add(a, b, 1);
+        } else if (x == 3) {
+            add(b, a, 0);
+        } else if (x == 4) {
+            add(b, a, 1);
+        } else if (x == 5) {
+            add(a, b, 0);
+        }
+        if (x % 2 == 0 && a == b) {
+            cout << -1 << endl;
+            exit(0);
+        }
+    }
+    for (int i = 1; i <= n; i++) {
+        vis[i] = 1;
+        dis[i] = 1;
+        used[i] = 1;
+        q.push(i);
+    }
+    while (!q.empty()) {
+        int z = q.front();
+        q.pop();
+        if (used[z] >= n - 1) {
+            cout << -1 << endl;
+            exit(0);
+        }
+        used[z]++;
+        for (int i = head[z]; i; i = g[i].next) {
+            int t = g[i].to;
+            if (dis[t] < dis[z] + g[i].val) {
+                dis[t] = dis[z] + g[i].val;
+                if (!vis[t]) {
+                    q.push(t);
+                    vis[t] = 1;
+                }
+            }
+        }
+        vis[z] = 0;
+    }
+    long long ans = 0;
+    for (int i = 1; i <= n; i++) {
+        ans += dis[i];
+    }
+    cout << ans << endl;
+    return 0;
+}