From 5860aae05150cb95b9a7e8990890b92eccb87ffd Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Thu, 24 Mar 2022 21:51:04 +0800
Subject: [PATCH] =?UTF-8?q?P1807=20=E6=9C=80=E9=95=BF=E8=B7=AF?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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R72243775
---
 Luogu/P1807/P1807.cpp | 50 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 Luogu/P1807/P1807.cpp

diff --git a/Luogu/P1807/P1807.cpp b/Luogu/P1807/P1807.cpp
new file mode 100644
index 00000000..924c5219
--- /dev/null
+++ b/Luogu/P1807/P1807.cpp
@@ -0,0 +1,50 @@
+#include <cstring>
+#include <iostream>
+#include <queue>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1505,
+          INF = 0x3f3f3f3f;
+
+int n, m, dist[N];
+std::vector<std::pair<int, int>> g[N];
+
+void spfa() {
+    memset(dist, 0xff, sizeof(dist));
+
+    std::queue<int> q;
+    q.push(1);
+    dist[1] = 0;
+
+    while (!q.empty()) {
+        int u = q.front();
+        q.pop();
+
+        for (auto e : g[u]) {
+            int v = e.first,
+                w = e.second;
+
+            if (dist[v] < dist[u] + w) {
+                dist[v] = dist[u] + w;
+                q.push(v);
+            }
+        }
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin >> n >> m;
+    for (int i = 1; i <= m; i++) {
+        int u, v, w;
+        cin >> u >> v >> w;
+        g[u].push_back(std::make_pair(v, w));
+    }
+    spfa();
+    cout << dist[n] << endl;
+    return 0;
+}