HDU 1690---Bus System(Floyd模板题+合理定义INF)

Floyd算法模板题，注意本题数据来到了10的9次方，保证两数相加不溢出，INF最好为1e20左右。

#include<iostream>#include<cstdio>#include<cmath>#include<algorithm>using namespace std;#define MAX 105#define INF (long long)1e20int n, m;long long d[MAX][MAX];void init(){for (int i = 0; i < n; i++)for (int j = 0; j < n; j++)d[i][j] = (i == j ? 0 : INF);}void floyd(){for (int k = 0; k < n; k++)for (int i = 0; i < n; i++)for (int j = 0; j < n; j++)if (d[i][k] < INF&&d[k][j]<INF&&d[i][j]>d[i][k] + d[k][j])d[i][j] = d[i][k] + d[k][j]; }int main(){int T; cin >> T;for (int num = 1; num <= T; num++){long long L[4], C[4];cin >> L[0] >> L[1] >> L[2] >> L[3] >> C[0] >> C[1] >> C[2] >> C[3];cin >> n >> m;init();int x[MAX];for (int i = 0; i < n; i++)  cin >> x[i];for(int i=0;i<n;i++)for (int j = i + 1; j < n; j++){if (abs(x[i] - x[j]) <= L[0])d[i][j] = d[j][i] = C[0];else if (abs(x[i] - x[j]) <= L[1])d[i][j] = d[j][i] = C[1];else if (abs(x[i] - x[j]) <= L[2])d[i][j] = d[j][i] = C[2];else if (abs(x[i] - x[j]) <= L[3])d[i][j] = d[j][i] = C[3];else d[i][j] = d[j][i] = INF;}floyd();printf("Case %d:\n", num);while (m--){int u, v; cin >> u >> v;u--; v--;if (d[u][v] != INF)printf("The minimum cost between station %d and station %d is %I64d.\n", u + 1, v + 1, d[u][v]);else printf("Station %d and station %d are not attainable.\n", u + 1, v + 1);}}system("pause");}