#184. 细菌

https://sjzezoj.com/submission/48512

S2OJ/184/184.cpp

@@ -0,0 +1,49 @@
+#include <cstring>
+#include <iostream>
+#include <queue>
+#include <vector>
+
+using std::cin;
+using std::cout;
+#define endl '\n'
+
+int n, x, dist[105];
+std::vector<std::pair<int, int>> g[105];
+bool vis[105];
+
+void spfa(int s) {
+    memset(dist, 0x3f, sizeof(dist));
+    std::queue<int> q;
+    q.push(s);
+    vis[s] = true;
+    dist[s] = 1;
+    while (!q.empty()) {
+        int u = q.front();
+        q.pop();
+        vis[u] = false;
+        for (auto e : g[u]) {
+            int v = e.first,
+                w = e.second;
+            if (dist[v] > std::max(1, (dist[u] + w + 1) / 2)) {
+                dist[v] = std::max(1, (dist[u] + w + 1) / 2);
+                if (!vis[v]) {
+                    q.push(v);
+                    vis[v] = true;
+                }
+            }
+        }
+    }
+}
+
+int main() {
+    cin >> n;
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= n; j++) {
+            cin >> x;
+            if (x) g[j].push_back(std::make_pair(i, -x));
+        }
+    }
+    spfa(n);
+    cout << dist[1] << endl;
+    return 0;
+}