Submission #244605

#	Time	Username	Problem	Language	Result	Execution time	Memory
244605		tqbfjotld	Potemkin cycle (CEOI15_indcyc)	C++14	100 / 100	951 ms	3072 KiB

indcyc

#include <bits/stdc++.h>
using namespace std;

int n,e;
vector<int> adjl[1005];
vector<int> cur;
int curpos[1005];
bool visited[1005][1005];
bool adjm[1005][1005];

int dfs(int node, int parent, int p2){
    if (visited[node][parent]) return -1;
    //printf("node %d, %d\n",node+1,curpos[node]);

    if (adjm[node][p2]) return -1;

    int k= -1;
    visited[node][parent] = true;
    for (auto x : adjl[node]){
        if (x==parent) continue;
        k = max(k,curpos[x]);
    }
    //printf("k: %d\n",k);
    if (k!=-1){
        cur.push_back(node);
       return k;
    }
    else{
        for (auto x : adjl[node]){
            if (x==parent) continue;
            curpos[x] = curpos[node]+1;
            //printf("set %d\n",1+x);
            int res = dfs(x,node,parent);
            //printf("received %d\n",res);
            if (res>0){
                cur.push_back(node);
                return res==curpos[node]?-2:res;
            }
            if (res==-2) return -2;
            curpos[x] = -1;

            //printf("reset %d\n",1+x);
        }
        return -1;
    }
}

int main(){
    scanf("%d%d",&n,&e);
    memset(curpos,-1,sizeof(curpos));
    for (int x = 0; x<e; x++){
        int a,b;
        scanf("%d%d",&a,&b);
        a--;b--;
        adjl[a].push_back(b);
        adjl[b].push_back(a);
        adjm[a][b] = true;
        adjm[b][a] = true;
    }
    for (int x = 0; x<n; x++){
        for (int y = 0; y<n; y++){
            if (!adjm[x][y]) continue;
        if(visited[x][y]) continue;
        curpos[x] = 1;
        if (dfs(x,y,-1)==-2){
            for (auto k : cur){
                printf("%d ",k+1);
            }
            return 0;
        }
        curpos[x] = -1;
        }
    }
    printf("no");

}

Compilation message (stderr)

indcyc.cpp: In function 'int main()':
indcyc.cpp:49:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&e);
     ~~~~~^~~~~~~~~~~~~~
indcyc.cpp:53:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&a,&b);
         ~~~~~^~~~~~~~~~~~~~

• 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: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10