1003 Emergence

题意要求出最短路径数目和最小花费。经典的Dijkstral算法变形。

// 1003. Emergency.cpp: 主项目文件。#include <cstdio>#include <cstring>const int N=501;const int INT_MAX=1<<30;int map[N][N];bool used[N];int people[N];int dist[N],resource[N],paths[N];int n,m,start,end;void dijsktral(){if(start==end){printf("1 %d\n",people[start]);return;}memset(used,0,sizeof(used));for(int i=0;i<n;i++){dist[i]=map[start][i];if(map[start][i]!=INT_MAX){resource[i]=people[start]+people[i];paths[i]=1;}else{resource[i]=0;paths[i]=0;}}resource[start]=people[start];used[start]=true;for(int i=1;i<n;i++){int min=INT_MAX,minf=-1;for(int j=0;j<n;j++){if(!used[j]&&dist[j]<min){min=dist[j];minf=j;}}used[minf]=true;if(minf==end)break;for(int j=0;j<n;j++){if(!used[j]){int distTemp=dist[minf]+map[minf][j],resourceTemp=resource[minf]+people[j];if(distTemp<dist[j]){dist[j]=distTemp;paths[j]=paths[minf];resource[j]=resourceTemp;}else if(distTemp==dist[j]){paths[j]=paths[minf]+paths[j];if(resourceTemp>resource[j])resource[j]=resourceTemp;}}}}printf("%d %d\n",paths[end],resource[end]);}int main(){while(~scanf("%d%d%d%d",&n,&m,&start,&end)){for(int i=0;i<n;i++)scanf("%d",people+i);for(int i=0;i<n;i++)for(int j=i;j<n;j++)map[i][j]=map[j][i]=INT_MAX;for(int i=0;i<m;i++){int from,to,dd;scanf("%d%d%d",&from,&to,&dd);if(map[from][to]>dd)map[from][to]=map[to][from]=dd;}dijsktral();}return 0;}