本题要求你实现一个天梯赛专属在线地图,队员输入自己学校所在地和赛场地点后,该地图应该推荐两条路线:一条是最快到达路线;一条是最短距离的路线。题目保证对任意的查询请求,地图上都至少存在一条可达路线。
输入格式:
输入在第一行给出两个正整数N(2 <= N <=500)和M,分别为地图中所有标记地点的个数和连接地点的道路条数。随后M行,每行按如下格式给出一条道路的信息:
V1 V2 one-way length time
其中V1和V2是道路的两个端点的编号(从0到N-1);如果该道路是从V1到V2的单行线,则one-way为1,否则为0;length是道路的长度;time是通过该路所需要的时间。最后给出一对起点和终点的编号。
输出格式:
首先按下列格式输出最快到达的时间T和用节点编号表示的路线:
Time = T: 起点 => 节点~1~ => ... => 终点
然后在下一行按下列格式输出最短距离D和用节点编号表示的路线:
Distance = D: 起点 => 节点~1~ => ... => 终点
如果最快到达路线不唯一,则输出几条最快路线中最短的那条,题目保证这条路线是唯一的。而如果最短距离的路线不唯一,则输出途径节点数最少的那条,题目保证这条路线是唯一的。
如果这两条路线是完全一样的,则按下列格式输出:
Time = T; Distance = D: 起点 => 节点~1~ => ... => 终点
输入样例1:
10 15
0 1 0 1 1
8 0 0 1 1
4 8 1 1 1
5 4 0 2 3
5 9 1 1 4
0 6 0 1 1
7 3 1 1 2
8 3 1 1 2
2 5 0 2 2
2 1 1 1 1
1 5 0 1 3
1 4 0 1 1
9 7 1 1 3
3 1 0 2 5
6 3 1 2 1
5 3
输出样例1:
Time = 6: 5 => 4 => 8 => 3
Distance = 3: 5 => 1 => 3
输入样例2:
7 9
0 4 1 1 1
1 6 1 3 1
2 6 1 1 1
2 5 1 2 2
3 0 0 1 1
3 1 1 3 1
3 2 1 2 1
4 5 0 2 2
6 5 1 2 1
3 5
输出样例2:
Time = 3; Distance = 4: 3 => 2 => 5
跟甲级题Online Map基本是同一道题,要求稍有不同。
代码:
#include <stdio.h> #include <string.h> #define inf 0x3f3f3f3f int m,n,source,destination,a,b,w,l,t; int length[501][501],times[501][501],dis[501],cost[501],dis1[501],num[501],vis[501],path1[501],path2[501]; void getpath1(int x) { if(x != source) { getpath1(path1[x]); printf(" => "); } printf("%d",x); } void getpath2(int x) { if(x != source) { getpath2(path2[x]); printf(" => "); } printf("%d",x); } int equals(int x) { if(path1[x] != path2[x])return 0; else if(x == source)return 1; return equals(path1[x]); } int main() { scanf("%d%d",&n,&m); for(int i = 0;i < n;i ++) { for(int j = 0;j < n;j ++) { length[i][j] = times[i][j] = inf; } dis[i] = cost[i] = dis1[i] = inf; path1[i] = path2[i] = -1; } for(int i = 0;i < m;i ++) { scanf("%d%d%d%d%d",&a,&b,&w,&l,&t); if(w) { length[a][b] = l; times[a][b] = t; } else { length[a][b] = length[b][a] = l; times[a][b] = times[b][a] = t; } } scanf("%d%d",&source,&destination); dis[source] = cost[source] = dis1[source] = 0; while(1) { int t = -1,mi = inf; for(int i = 0;i < n;i ++) { if(!vis[i] && mi > cost[i]) { mi = cost[i]; t = i; } } if(t == -1)break; vis[t] = 1; for(int i = 0;i < n;i ++) { if(vis[i] || times[t][i] == inf)continue; if(cost[i] > cost[t] + times[t][i]) { path2[i] = t; cost[i] = cost[t] + times[t][i]; dis1[i] = dis1[t] + length[t][i]; } else if(cost[i] == cost[t] + times[t][i] && dis1[i] > dis1[t] + length[t][i]) { dis1[i] = dis1[t] + length[t][i]; path2[i] = t; } } } memset(vis,0,sizeof(vis)); while(1) { int t = -1,mi = inf; for(int i = 0;i < n;i ++) { if(!vis[i] && mi > dis[i]) { mi = dis[i]; t = i; } } if(t == -1)break; vis[t] = 1; for(int i = 0;i < n;i ++) { if(vis[i] || length[t][i] == inf)continue; if(dis[i] > dis[t] + length[t][i]) { path1[i] = t; dis[i] = dis[t] + length[t][i]; num[i] = num[t] + 1; } else if(dis[i] == dis[t] + length[t][i] && num[i] > num[t] + 1) { num[i] = num[t] + 1; path1[i] = t; } } } printf("Time = %d",cost[destination]); if(!equals(destination)) { printf(": "); getpath2(destination); printf("\n"); } else { printf("; "); } printf("Distance = %d: ",dis[destination]); getpath1(destination); }
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