提出 #45438798

---

ソースコード 拡げる

#include<bits/stdc++.h>
#define LL long long
#define DB double
#define MOD 998244353
#define ls(x) x << 1
#define rs(x) x << 1 | 1
#define lowbit(x) x & (-x)
#define PII pair<int, int>
#define MP make_pair
#define VI vector<int>
#define VII vector<int>::iterator
#define all(x) x.begin(), x.end()
#define EB emplace_back
#define SI set<int>
#define SII set<int>::iterator
#define QI queue<int>
using namespace std;
template<typename T> void chkmn(T &a, const T &b) { (a > b) && (a = b); }
template<typename T> void chkmx(T &a, const T &b) { (a < b) && (a = b); }
int inc(const int &a, const int &b) { return a + b >= MOD ? a + b - MOD : a + b; }
int dec(const int &a, const int &b) { return a - b < 0 ? a - b + MOD : a - b; }
int mul(const int &a, const int &b) { return 1LL * a * b % MOD; }
int sqr(const int &a) { return 1LL * a * a % MOD; }
void Inc(int &a, const int &b) { ((a += b) >= MOD) && (a -= MOD); }
void Dec(int &a, const int &b) { ((a -= b) < 0) && (a += MOD); }
void Mul(int &a, const int &b) { a = 1LL * a * b % MOD; }
void Sqr(int &a) { a = 1LL * a * a % MOD; }
int qwqmi(int x, int k = MOD - 2)
{
    int res = 1;
    while(k)
    {
        if(k & 1) Mul(res, x);
        Sqr(x), k >>= 1;
    }
    return res;
}
const int N = 1e6 + 5;
int n, m;
set<int> G[N];
set<int> S;
int w[N], wcnt;
queue<int> q;
int d[N];
set<int> s[N];
int f[N];
int main()
{
	scanf("%d %d", &n, &m);
	for(int i = 1; i <= m; ++i)
	{
		int x, y;
		scanf("%d %d", &x, &y);
		G[x].insert(y);
		G[y].insert(x);
	}
	for(int i = 1; i <= n; ++i)
		S.insert(i);
	q.push(1);
	S.erase(1);
	while(!q.empty())
	{
		int u = q.front();
		q.pop();
		wcnt = 0;
		for(auto v : S) w[++wcnt] = v;
		for(int i = 1; i <= wcnt; ++i)
		{
			int v = w[i];
			if(G[u].find(v) == G[u].end())
			{
				q.push(v);
				d[v] = d[u] + 1;
				S.erase(v);
			}
		}
		if(S.empty())
			break;
	}
	if(d[n] == 0)
	{
		puts("-1");
		return 0;
	}
	for(int i = 1; i <= n; ++i)
		s[d[i]].insert(i);
	int sum = 1;
	f[1] = 1;
	for(int i = 1; i <= n; ++i)
	{
		int res = 0;
		for(SII it = s[i].begin(); it != s[i].end(); ++it)
		{
			int u = *it;
			f[u] = sum;
			for(SII _it = G[u].begin(); _it != G[u].end(); ++_it)
			{
				int v = *_it;
				if(d[v] == i - 1)
					Dec(f[u], f[v]);
			}
			Inc(res, f[u]);
		}
		sum = res;
	}
	printf("%d\n", f[n]);
    return 0;
}

提出情報

コンパイルエラー

Main.cpp: In function ‘int main()’:
Main.cpp:49:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   49 |         scanf("%d %d", &n, &m);
      |         ~~~~~^~~~~~~~~~~~~~~~~
Main.cpp:53:22: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   53 |                 scanf("%d %d", &x, &y);
      |                 ~~~~~^~~~~~~~~~~~~~~~~

ジャッジ結果