Codeforces Round #287 (Div. 2) 507 E. Breaking Good

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写的感觉比以前进步许多，就是遍历邻接表的时候感觉是不是要用堆优化一下，第一次交超时了，郁闷了一阵，突然发现忘了把本地测试的#define删掉了，又试了一次就AC了，这题其实就是个BFS，多维护了一个需要修的路的条数，算法上没什么难度

#include<iostream>#include<string>#include<cstring>#include<iomanip>#include<cstdio>#include<algorithm>#include<vector>#include<cmath>#include<set>#include<ctime>#include<cctype>#include<memory>#include<cstdlib>#include<map>#include<list>#include<queue>#include<stack>#include<climits>#define INF 0x7fffffff#define db puts("debug");#define FOR(s,n) for(int i=(s);i<(n);i++)#define FOR2(s,n) for(int j=(s);j<(n);j++)typedef long long i64;#define MX 100005using namespace std;struct edge{    edge(int f,int t,bool s){        from=f;        to=t;        stg=s;        printed=0;    }    int from,to;    bool printed,stg;};vector<edge> G[MX];int dis[MX];int prev[MX];int mcost[MX];int n,m;queue<int> nods;void update(int now){    int sz=G[now].size();    vector<edge> &ve=G[now];    FOR(0,sz){        edge &e=ve[i];        if(dis[e.from]+1<dis[e.to]||(dis[e.from]+1==dis[e.to]&&mcost[e.from]+!e.stg<mcost[e.to])){            prev[e.to]=e.from;            mcost[e.to]=mcost[e.from]+!e.stg;            dis[e.to]=dis[e.from]+1;            nods.push(e.to);        }    }}int main(){#ifdef LOCAL    freopen("in.txt","r",stdin);   // freopen("out.txt","w",stdout);#endif // LOCAL    cin>>n>>m;    int x,y,s;    int r1=0;    FOR(0,m){        scanf("%d%d%d",&x,&y,&s);        G[x].push_back(edge(x,y,s));        G[y].push_back(edge(y,x,s));        if(s==1)            r1++;    }    memset(dis,0x3f,sizeof dis);    dis[1]=0;    nods.push(1);    int now;    while(!nods.empty()){        now=nods.front();        nods.pop();        update(now);    }    cout<<r1-dis[n]+2*mcost[n]<<endl;    int t=n,f;    while(t!=1){        f=prev[t];        vector<edge> &ve=G[min(f,t)];        FOR(0,ve.size()){            if(ve[i].to==max(f,t)){                if(ve[i].stg==1){                    ve[i].printed=1;                    break;                }                printf("%d %d %d\n",ve[i].from,ve[i].to,!ve[i].stg);                ve[i].printed=1;                break;            }        }        t=prev[t];    }    FOR(1,n+1){        vector<edge> &ve=G[i];        FOR2(0,ve.size()){            edge &e=ve[j];            if(e.from>e.to)                continue;            if(!e.printed&&e.stg==1)                printf("%d %d %d\n",e.from,e.to,0);        }    }    return 0;}

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