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#178009#5458. Shortest Path QueryClHg2WA 42ms12076kbC++142.4kb2023-09-13 17:14:092024-06-21 12:38:18

Judging History

你现在查看的是最新测评结果

  • [2024-06-21 12:38:18]
  • 管理员手动重测本题所有提交记录
  • 测评结果:WA
  • 用时:42ms
  • 内存:12076kb
  • [2023-09-13 17:14:09]
  • 评测
  • 测评结果:0
  • 用时:42ms
  • 内存:12080kb
  • [2023-09-13 17:14:09]
  • 提交

answer

#include <algorithm>
#include <cstdint>
#include <iostream>
#include <stack>
#include <utility>
#include <vector>

namespace {
using std::cin;
using std::cout;
using std::int64_t;

const int kMaxN = 5.0e4 + 5, kInf = 1.0e9 + 5;
int n, m, q;
int deg[kMaxN];
std::vector<std::pair<int, int>> edges[kMaxN];

struct Point {
  int x, y;
  Point(int x, int y) : x(x), y(y) {}
};

inline bool operator==(const Point &a, const Point &b) {
  return a.x == b.x && a.y == b.y;
}

inline bool operator<(const Point &a, const Point &b) {
  return a.x == b.x ? a.y < b.y : a.x < b.x;
}

std::vector<Point> paths[kMaxN];

std::vector<Point> ConvexHull(std::vector<Point> polygon) {
  std::sort(polygon.begin(), polygon.end());
  polygon.erase(std::unique(polygon.begin(), polygon.end()), polygon.end());
  std::vector<Point> convex_hull;

  auto check = [](const Point &a, const Point &b, const Point &c) {
    return int64_t{a.y - b.y} * (c.x - b.x) >= int64_t{b.y - c.y} * (b.x - a.x);
  };

  for (const Point &a : polygon) {
    while (convex_hull.size() >= 2 &&
           check(convex_hull.end()[-2], convex_hull.back(), a)) {
      convex_hull.pop_back();
    }

    convex_hull.emplace_back(a);
  }

  return convex_hull;
}

void Topo() {
  std::stack<int, std::vector<int>> stk;

  for (int i = 1; i <= n; ++i) {
    if (deg[i] == 0) paths[i].emplace_back(0, 0), stk.emplace(i);
  }

  while (!stk.empty()) {
    int u = stk.top();
    stk.pop();
    paths[u] = ConvexHull(std::move(paths[u]));

    for (const auto &edge : edges[u]) {
      int v = edge.first, w = edge.second;

      if (w == 0) {
        for (const Point &path : paths[u]) {
          paths[v].emplace_back(path.x + 1, path.y);
        }
      } else {
        for (const Point &path : paths[u]) {
          paths[v].emplace_back(path.x, path.y + 1);
        }
      }

      if (--deg[v] == 0) stk.emplace(v);
    }
  }
}
}  // namespace

int main() {
  cin.tie(nullptr);
  std::ios::sync_with_stdio(false);
  cin >> n >> m;

  while (m--) {
    int u, v, w;
    cin >> u >> v >> w, ++deg[v];
    edges[u].emplace_back(v, w);
  }

  Topo();
  cin >> q;

  while (q--) {
    int a, b, u;
    cin >> a >> b >> u;
    int ans = kInf;

    for (const Point &path : paths[u]) {
      ans = std::min(ans, a * path.x + b * path.y);
    }

    cout << ans << "\n";
  }

  return 0;
}

详细

Test #1:

score: 100
Accepted
time: 1ms
memory: 5964kb

input:

4 4
1 2 0
1 3 1
2 4 0
3 4 1
3
3 5 2
3 2 4
2 3 4

output:

3
4
4

result:

ok 3 number(s): "3 4 4"

Test #2:

score: -100
Wrong Answer
time: 42ms
memory: 12076kb

input:

50000 100000
1 2 1
2 3 0
3 4 1
4 5 0
5 6 1
6 7 0
7 8 1
8 9 1
9 10 0
10 11 1
11 12 1
12 13 1
13 14 0
14 15 0
15 16 0
16 17 0
17 18 1
18 19 1
19 20 0
20 21 1
21 22 0
22 23 0
23 24 1
24 25 1
25 26 0
26 27 1
27 28 0
28 29 0
29 30 0
30 31 0
31 32 1
32 33 0
33 34 1
34 35 1
35 36 1
36 37 1
37 38 0
38 39 0
...

output:

171090050
250459598
258589143
259699419
104338880
16685198
59196446
64713954
46949896
245672377
94777502
84753103
267419449
192242757
216482422
147454419
111021650
80187604
247374700
111782626
121405290
249524638
191332392
202049239
343798460
173714177
174899498
97998224
96431009
280559577
164349486...

result:

wrong answer 1st numbers differ - expected: '164602050', found: '171090050'