POJ-3159 (+ Dijikstra differential constraint optimization)

Candies

POJ-3159

Here is an application of graph theory, which is the difference constraints. FIG converted by a differential constraint, then the form of linked lists Dijikstra optimization algorithm rather than vector form (or timeout).

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<vector>
#include<queue>
using namespace std;
const int INF=0x3f3f3f3f;
int n,m;
struct edge{
    int to;
    int cost;
    int next;
};
struct node{
    int dis;
    int to;
    node(){}
    node(int a,int b):dis(a),to(b){}
    bool operator<(const node& t)const{
        return dis>t.dis;
    }
};
edge ma[150005];
int head[30004];
int top;//指向头结点
int d[30004];
void addedge(int a,int b,int c){
    ma[top].to=b;
    ma[top].cost=c;
    ma[top].next=head[a];
    head[a]=top;
    top++;
}
void dijikstra(int s){
    priority_queue<node> que;
    for(int i=1;i<=n;i++){
        d[i]=INF;
    }
    d[s]=0;
    que.push(node(0,s));
    while(!que.empty()){
        node temp=que.top();
        que.pop();
        int v=temp.to;
        if(d[v]<temp.dis)
            continue;
        for(int h=head[v];h!=-1;h=ma[h].next){
            edge e=ma[h];
            if(d[e.to]>d[v]+e.cost){
                d[e.to]=d[v]+e.cost;
                que.push(node(d[e.to],e.to));
            }
        }
    }
}
int main(){
    memset(head,-1,sizeof(head));
    top=0;
    scanf("%d%d",&n,&m);
    int a,b,c;
    for(int i=0;i<m;i++){
        scanf("%d%d%d",&a,&b,&c);
        addedge(a,b,c);
    }
    dijikstra(1);
    cout<<d[n]<<endl;
    //system("pause");
    return 0;
}