#include <vector>
#include <map>
#include <set>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <string>
#include <cctype>
#include <cstring>
#include <queue>
#include <cassert>
using namespace std;
typedef long long LL;
typedef vector<string> VS;
typedef vector<int> VI;
typedef pair<int,int> PII;
typedef vector<PII> VPII;
#define MP make_pair
#define ST first
#define ND second
#define PB push_back
#define FOR(i,a,b) for( int i=(a); i<(b); ++i)
#define FORD(i,a,b) for( int i=(a); i>(b); --i)
#define REP(i,n) for(int i=0; i<(n); ++i)
#define ALL(X) (X).begin(),(X).end()
#define SZ(X) (int)(X).size()
#define FORE(it,X) for(__typeof((X).begin()) it=(X).begin(); it!=(X).end();++it)
int dy[100005];
VI dt[100005];
int n,m;
int main()
{
cin>>n>>m;
REP(i, m) {
int a,b;
scanf("%d%d",&a,&b);
a--,b--;
dt[a].PB(b);
}
dy[0]=1;
REP(i, n) if (dy[i]) {
REP(j, SZ(dt[i])) {
int v= dt[i][j];
if (dy[v]) dy[v] = min(dy[v], dy[i]+1);
else dy[v] = dy[i]+1;
}
}
if (dy[n-1] == 0) cout<<-1<<endl;
else cout<<dy[n-1]-1<<endl;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
4412 KB |
Output is correct |
2 |
Correct |
0 ms |
4412 KB |
Output is correct |
3 |
Correct |
0 ms |
4412 KB |
Output is correct |
4 |
Correct |
0 ms |
4412 KB |
Output is correct |
5 |
Correct |
0 ms |
4412 KB |
Output is correct |
6 |
Correct |
0 ms |
4412 KB |
Output is correct |
7 |
Correct |
0 ms |
4412 KB |
Output is correct |
8 |
Correct |
0 ms |
4412 KB |
Output is correct |
9 |
Correct |
0 ms |
4412 KB |
Output is correct |
10 |
Correct |
16 ms |
4948 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
4412 KB |
Output is correct |
2 |
Correct |
28 ms |
7448 KB |
Output is correct |
3 |
Correct |
56 ms |
7448 KB |
Output is correct |
4 |
Correct |
52 ms |
7448 KB |
Output is correct |
5 |
Correct |
56 ms |
7448 KB |
Output is correct |
6 |
Correct |
16 ms |
7448 KB |
Output is correct |
7 |
Correct |
44 ms |
7448 KB |
Output is correct |
8 |
Correct |
76 ms |
7580 KB |
Output is correct |
9 |
Correct |
32 ms |
7448 KB |
Output is correct |
10 |
Correct |
64 ms |
7184 KB |
Output is correct |