提出 #7878842

---

ソースコード 拡げる

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

#define REP(i, stop) for (signed i = 0; i < stop; ++i)

#define S(i, j) ip[i * (N + 1) + j]

const signed is = 1 << 16;
char ib[is], *ip = ib, it;

using P = pair<int, int>;
signed N;
queue<P> que;
int parity[200];
P bfs(int s) {
	REP(i, N) parity[i] = -1;
	P p;
	que.push({s, 1});
	parity[s] = 0;
	while (!que.empty()) {
		p = que.front();
		que.pop();
		int i = p.first;
		int d = p.second;
		REP(j, N) {
			if (S(i, j) == '0') continue;
			if (parity[j] == -1) {
				parity[j] = 1 - parity[i];
				que.push({j, d + 1});
			} else if (parity[i] == parity[j]) {
				puts("-1\n");
				exit(0);
			}
		}
	}
	return p;
}

signed main() {
	fread_unlocked(ib, 1, is, stdin);
	while ((it = *ip++) != '\n') {
		N = N * 10 + it - '0';
	}
	P p = bfs(1);
	p = bfs(p.first);
	printf("%d\n", p.second);
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘int main()’:
./Main.cpp:40:34: warning: ignoring return value of ‘size_t fread_unlocked(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
  fread_unlocked(ib, 1, is, stdin);
                                  ^

ジャッジ結果