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| #include <iostream>
#include <vector>
#include <queue>
#include <bitset>
#include <algorithm>
#include <cmath>
using namespace std;
struct Node {
int id = -1;
int d = -1;
vector<int> neighbors;
vector<int> edges;
};
struct NodeCmp {
bool operator()(const Node &a, const Node &b) const {
return b.d < a.d;
}
};
int dijkstra(Node* graph, int N, int s, int t) {
bitset<100001> set;
set.reset();
priority_queue<Node, vector<Node>, NodeCmp> heap;
graph[s].d = 0;
set[s] = 1;
for (int i = 0; i < graph[s].neighbors.size(); i++) {
graph[graph[s].neighbors[i]].d = graph[s].edges[i];
heap.push(graph[graph[s].neighbors[i]]);
}
int i = 0;
while (i < N - 1) {
Node nearestNode = heap.top();
heap.pop();
if (set[nearestNode.id])
continue;
i++;
set[nearestNode.id] = 1;
for (int j = 0; j < nearestNode.neighbors.size(); j++) {
if (graph[nearestNode.neighbors[j]].d == -1 || nearestNode.edges[j] + nearestNode.d < graph[nearestNode.neighbors[j]].d)
graph[nearestNode.neighbors[j]].d = nearestNode.edges[j] + nearestNode.d;
heap.push(graph[nearestNode.neighbors[j]]);
}
}
return graph[t].d;
}
struct Point {
int id = 0;
int x = 0;
int y = 0;
Point(int i, int xv, int yv) {
id = i;
x = xv;
y = yv;
}
};
bool xComp(const Point &a, const Point &b) {
return a.x < b.x;
}
bool yComp(const Point &a, const Point &b) {
return a.y < b.y;
}
int main() {
int N = 0;
cin >> N;
vector<Point> coord;
for (int i = 1; i < N + 1; i++) {
int x = 0, y = 0;
cin >> x >> y;
coord.push_back(Point(i, x, y));
}
Node* graph = new Node[N + 1];
for (int i = 0; i < N + 1; i++)
graph[i].id = i;
sort(coord.begin(), coord.end(), xComp);
for (int i = 0; i < N - 1; i++) {
int a = coord[i].id;
int b = coord[i + 1].id;
int edge = min(abs(coord[i].x - coord[i + 1].x), abs(coord[i].y - coord[i + 1].y));
graph[a].neighbors.push_back(b);
graph[a].edges.push_back(edge);
graph[b].neighbors.push_back(a);
graph[b].edges.push_back(edge);
}
sort(coord.begin(), coord.end(), yComp);
for (int i = 0; i < N - 1; i++) {
int a = coord[i].id;
int b = coord[i + 1].id;
int edge = min(abs(coord[i].x - coord[i + 1].x), abs(coord[i].y - coord[i + 1].y));
graph[a].neighbors.push_back(b);
graph[a].edges.push_back(edge);
graph[b].neighbors.push_back(a);
graph[b].edges.push_back(edge);
}
cout << dijkstra(graph, N, 1, N) << endl;
return 0;
}
|
