Submission #230768

#	Time	Username	Problem	Language	Result	Execution time	Memory
230768		nicolaalexandra	Potemkin cycle (CEOI15_indcyc)	C++14	80 / 100	1097 ms	6016 KiB

indcyc

#include <bits/stdc++.h>
#define DIM 1010
#define DIMBUFF 7000000
#define INF 2000000000
using namespace std;
//FILE *fin = fopen ("date.in","r");
//FILE *fout = fopen ("date.out","w");
FILE *fin = stdin;
FILE *fout = stdout;

vector <int> L[DIM];
int dist[DIM],t[DIM],a[DIM][DIM],c[DIM],sol[DIM];
pair <int,int> mch[DIM*DIM];
int n,m,x,y,i,j,k,ok,pos,el;
char buff[DIMBUFF];

int bfs (int start){

    for (int i=1;i<=n;i++){
        dist[i] = INF;
        t[i] = 0;
    }
    int p = 1, u = 0;
    c[++u] = start;
    dist[start] = 0;
    int ok = 0, val;

    while (p <= u){
        int nod = c[p];
        p++;
        for (auto vecin : L[nod]){

            if (dist[vecin] == INF && a[nod][vecin]){
                dist[vecin] = 1 + dist[nod];
                t[vecin] = nod;

                if (a[vecin][x]){
                    if (dist[vecin] > 1){
                        val = vecin;

                        while (val){
                            fprintf(fout,"%d ",val);
                            val = t[val];
                        }

                        return 1;
                    }
                } else c[++u] = vecin;
            }}}

    return 0;
}
int get_nr(){
    while(!(buff[pos] >= '0' && buff[pos] <= '9'))
        pos++;
    int nr = 0;
    while (buff[pos] >= '0' && buff[pos] <= '9'){
        nr = nr*10 + buff[pos] - '0';
        pos++;
    }
    return nr;
}
int main (){

    fread (buff,1,DIMBUFF,fin);
    //cin>>n>>m;
    n = get_nr(), m = get_nr();
    for (i=1;i<=m;++i){
        //cin>>x>>y;
        x = get_nr(), y = get_nr();
        L[x].push_back(y);
        L[y].push_back(x);
        a[x][y] = a[y][x] = 1;
        mch[i] = make_pair (x,y);
    }

    for (i=1;i<=m;i++){
        x = mch[i].first, y = mch[i].second;
        a[x][y] = a[y][x] = 0;

        if (bfs(y)){ /// am gasit un drum ok

            fprintf(fout,"%d ",x);

            return 0;
        }

        a[x][y] = a[y][x] = 1;
    }

    fprintf(fout,"no");

    return 0;
}

Compilation message (stderr)

indcyc.cpp: In function 'int bfs(int)':
indcyc.cpp:26:9: warning: unused variable 'ok' [-Wunused-variable]
     int ok = 0, val;
         ^~
indcyc.cpp: In function 'int main()':
indcyc.cpp:65:11: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     fread (buff,1,DIMBUFF,fin);
     ~~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 10 / 10
• Subtask 10: 0 / 10