Submission #1938483

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Source Code Expand

#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <functional>
#include <utility>
#include <tuple>
#include <cctype>
using namespace std;
#define INF 0x3f3f3f3f
#define INFLL 0x3f3f3f3f3f3f3f3fLL
#define MOD 1000000007
#define mp make_pair
#define mt make_tuple
#define pb push_back
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pint;
typedef pair<ll,ll> pll;
typedef tuple<int,int,int> tint;
typedef vector<int> vint;
typedef vector<ll> vll;
int dx[8]={0,0,-1,1,1,1,-1,-1};
int dy[8]={-1,1,0,0,1,-1,1,-1};
const int SIZE=2550;
//ここまでテンプレ
#define REP(i,n) for(int i=0;i<(int)n;++i)
#define FOR(i,c) for(auto i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
typedef int Weight;
struct Edge {
  int src, dst;
  Weight weight;
  Edge(int src, int dst, Weight weight) :
    src(src), dst(dst), weight(weight) { }
};
bool operator < (const Edge &e, const Edge &f) {
  return e.weight != f.weight ? e.weight > f.weight : // !!INVERSE!!
    e.src != f.src ? e.src < f.src : e.dst < f.dst;
}
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

typedef vector<Weight> Array;
typedef vector<Array> Matrix;
void shortestPath(const Graph &g, int s,
    vector<Weight> &dist, vector<int> &prev) {
  int n = g.size();
  dist.assign(n, INF); dist[s] = 0;
  prev.assign(n, -1);
  priority_queue<Edge> Q; // "e < f" <=> "e.weight > f.weight"
  for (Q.push(Edge(-2, s, 0)); !Q.empty(); ) {
    Edge e = Q.top(); Q.pop();
    if (prev[e.dst] != -1) continue;
    prev[e.dst] = e.src;
    FOR(f,g[e.dst]) {
      if (dist[f->dst] > e.weight+f->weight) {
        dist[f->dst] = e.weight+f->weight;
        Q.push(Edge(f->src, f->dst, e.weight+f->weight));
      }
    }
  }
}
vector<int> buildPath(const vector<int> &prev, int t) {
  vector<int> path;
  for (int u = t; u >= 0; u = prev[u])
    path.push_back(u);
  reverse(path.begin(), path.end());
  return path;
}
int main(){
	int N,M,R,T;
	cin>>N>>M>>R>>T;
	Graph G;
	for(int i=0;i<N;i++){
		Edges E;
		G.pb(E);
	}
	for(int i=0;i<M;i++){
		int a,b,c;
		cin>>a>>b>>c;
		a--,b--;
		G[a].pb(Edge(a,b,c));
		G[b].pb(Edge(b,a,c));
	}
	vint D[SIZE],P[SIZE];
	//全点対間について最短距離を求めてソートする
	for(int i=0;i<N;i++){
		shortestPath(G,i,D[i],P[i]);
		sort(D[i].begin(),D[i].end());
	}
	ll ans=0;
	//各点を目的地にして回す
	for(int DES=0;DES<N;DES++){
		//各店を亀の始点にして回す
		for(int TUR=0;TUR<N;TUR++){
			//目的地と亀の始点が同じときはスキップ
			if(TUR==0)
				continue;
			//ウサギより亀が速くゴールするようなウサギの始点を二分探索
			int ng=0,ok=N;
			while(ok-ng>1){
				int RAB=(ok+ng)/2;
				if(D[DES][RAB]*T>D[DES][TUR]*R)
					ok=RAB;
				else
					ng=RAB;
			}
			//ウサギの始点集合の数
			ll temp=N-ok;
			//亀の始点がウサギの始点集合の中にあるなら1引いておく
			if(ok<=TUR)
				temp--;
			ans+=temp;
		}
	}
	cout<<ans<<endl;
	return 0;
}

Submission Info

Judge Result