同余最短路

• #A P3403 跳楼机
• #B P2662 牛场围栏
• #C P2371 [国家集训队]墨墨的等式
• #D P4156 [WC2016]论战捆竹竿

跳楼机

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<queue>
#include<cstdlib>
#include<stack>
using namespace std;
typedef long long LL;
LL h,d[100005],cnt;
int x,y,z,hd[100005],a[15];
struct Edge{
    LL to, nxt, w;
}edge[2000005];
struct Point{
    LL val;
    int s;
    Point(){}
    Point(LL VAL,int S){val=VAL,s=S;}
    bool operator < (Point another) const {
        return val>another.val;
    }//
};
void add(int u, int v, int w){
    cnt++;
    edge[cnt].to = v;
    edge[cnt].nxt = hd[u];
    edge[cnt].w = w;
    hd[u] = cnt;
}
void Dijkstra(LL s){
    memset(d,63,sizeof d);
    d[0]=0;
    priority_queue<Point> Q;
    Q.push(Point(0,s));
    while(!Q.empty()){
        Point now=Q.top(); Q.pop();
        int p=now.s;
        LL val=now.val;
        if(val<d[p])    continue;
        for(int i = hd[p]; i; i = edge[i].nxt){
            int v = edge[i].to;
            if(d[v] > d[p] + edge[i].w){//err: (dis[u] + edge[i].w)%x
                d[v] = d[p] + edge[i].w;
                Q.push(Point(d[p] + edge[i].w, v));
            }
        }
    }
}
int main(){
    scanf("%lld %d %d %d",&h,&x,&y,&z);
    a[1]=x,a[2]=y,a[3]=z;
    sort(a+1,a+4);
    x=a[1],y=a[2],z=a[3];
    if(x == 1 || y==1 || z==1) {printf("%lld",h);return 0;}
    ////所以0 - x 这些点和其他点之间已知的的关系
    for(int i=0;i<x;++i)
        add(i, (i + y)%x, y), add(i, (i + z)%x, z);
    Dijkstra(0);
    LL ans=0;
    for(int i=0;i<x;++i)
        if(d[i]-1<=h)    ans+=(h-d[i]-1)/x+1;
    printf("%lld",ans);
    return 0;
}