Initial commit: C++ courseware

2.Course/2.深入浅出程序设计竞赛（提高篇）/最短路/C++源码/07_01_p1144.cpp

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+// P1144 最短路计数。C++17；无向无权图，重边按不同边计数。
+#include <bits/stdc++.h>
+using namespace std;
+int main() {
+    ios::sync_with_stdio(false); cin.tie(nullptr);
+    int n, m; if (!(cin >> n >> m)) return 0;
+    vector<int> head(n + 1, -1), to(2 * m), nxt(2 * m);
+    int tot = 0;
+    auto add = [&](int u, int v) {
+        to[tot] = v; nxt[tot] = head[u]; head[u] = tot++;
+    };
+    for (int i = 0, u, v; i < m; ++i) {
+        cin >> u >> v; add(u, v); add(v, u);
+    }
+    vector<int> dist(n + 1, -1), ways(n + 1, 0);
+    queue<int> q; dist[1] = 0; ways[1] = 1; q.push(1);
+    while (!q.empty()) {
+        int u = q.front(); q.pop();
+        for (int e = head[u]; e != -1; e = nxt[e]) {
+            int v = to[e];
+            if (dist[v] == -1) {
+                dist[v] = dist[u] + 1; q.push(v);
+            }
+            if (dist[v] == dist[u] + 1)
+                ways[v] = (ways[v] + ways[u]) % 100003;
+        }
+    }
+    for (int i = 1; i <= n; ++i) cout << ways[i] << '\n';
+}