NewCodeTemplate

模板/其他/比较函数的模板6种.cpp

@@ -0,0 +1,34 @@
+1
+auto cmp = [&](const Edge& a, const Edge& b) {
+    return a.cost > b.cost;   // 小根堆：cost 小的优先
+};
+
+priority_queue<Edge, vector<Edge>, decltype(cmp)> pq(cmp);
+
+2
+struct Compare {
+    bool operator()(const Edge& a, const Edge& b) const {
+        return a.cost > b.cost;   // 小根堆
+    }
+};
+
+priority_queue<Edge, vector<Edge>, Compare> pq;
+
+3
+using F = function<bool(const Edge&, const Edge&)>;
+priority_queue<Edge, vector<Edge>, F> pq(
+    [](const Edge& a, const Edge& b){
+        return a.cost > b.cost;  // 小根堆
+    }
+);
+
+4
+struct Edge{
+    int from, to, cost;
+    Edge(int f, int t, int c): from(f), to(t), cost(c) {}
+
+    bool operator<(const Edge& other) const {
+        return cost > other.cost;  // 小根堆
+    }
+    //一定是<，不能是>
+}