POJ 3159 Candies

来源：互联网发布：美的面试知乎编辑：程序博客网时间：2024/06/05 16:37

题目来源

题意：给N个人分水果，一共M组数据。每组数据包含A、B、C。B的糖果数-A的糖果数<=C。最后求N比1最多多多少糖果。

注意：存边一定要用前向星。

（1）spfa+优先队列

（2）dijkstra优先队列

#include <iostream>#include <stdio.h>#include <string.h>#include <queue>#include <algorithm>#include <stack>#include <map>#include <set>#include <vector>#include <math.h>#define inf 0x3f3f3f3f#define ll long long#define mod 99991#define N 51000using namespace std;int n,m;struct node{    int to;    int w;    int next;}e[150010];int head[30010];int dis[31000];bool vis[31000];int Top;void init(){    memset(head,-1,sizeof(head));    Top = 0;}void add(int u,int v,int w){    e[Top].to = v;    e[Top].w = w;    e[Top].next = head[u];    head[u] = Top++;}void spfa(){    memset(dis,inf,sizeof(dis));    memset(vis,false,sizeof(vis));    priority_queue<int>q;    q.push(1);    dis[1] = 0;    vis[1] = true;    while(!q.empty()){        int u = q.top();        q.pop();        vis[u] = false;        for(int i = head[u]; ~i; i = e[i].next){            int v = e[i].to;            int w = e[i].w;            if(dis[v] > dis[u]+w){                dis[v] = dis[u]+w;                if(!vis[v]){                    q.push(v);                    vis[v] = true;                }            }        }    }    printf("%d\n",dis[n]);}int main(){    int a,b,c;    while(~scanf("%d%d",&n,&m)){        init();        while(m--){            scanf("%d%d%d",&a,&b,&c);            add(a,b,c);        }        spfa();    }    return 0;}

#include <iostream>#include <stdio.h>#include <string.h>#include <queue>#include <algorithm>#include <stack>#include <map>#include <set>#include <vector>#include <math.h>#define inf 0x3f3f3f3f#define ll long long#define mod 99991#define N 51000using namespace std;int n,m;struct node{    int to;    int w;    int next;    bool operator < (const node &b)const{        return w > b.w;    }}now,next,e[150001];int head[31000];int dis[31000];bool vis[31000];int Top = 0;void add(int u,int v,int w){    e[Top].to = v;    e[Top].w = w;    e[Top].next = head[u];    head[u] = Top++;}void dijkstra(){    memset(dis,inf,sizeof(dis));    memset(vis,false,sizeof(vis));    priority_queue<node>q;    dis[1] = 0;    now.to = 1;    now.w = 0;    q.push(now);    while(!q.empty()){        now = q.top();        q.pop();        int u = now.to;        if(vis[u])continue;        vis[u] = true;        for(int i = head[u]; ~i; i=e[i].next){            int v = e[i].to;            int w = e[i].w;            if(dis[v] > dis[u]+w){                dis[v] = dis[u]+w;                next.to = v;                next.w = dis[v];                q.push(next);            }        }    }    printf("%d\n",dis[n]);}int main(){    int a,b,c;    while(~scanf("%d%d",&n,&m)){        memset(head,-1,sizeof(head));        Top = 0;        while(m--){            scanf("%d%d%d",&a,&b,&c);            add(a,b,c);        }        dijkstra();    }    return 0;}

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