Submission #2273155

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Source Code Expand

#include <cstdio>
#include <vector>
#include <algorithm>
#include <functional>
#include <map>
#include <set>
#include <string>
#include <iostream>
#include <cassert>
#include <cmath>
using namespace std;

void ng() {
        printf("-1\n");
        exit(0);
}

int main() {
        int n;
        scanf("%d", &n);
        vector<set<int>> ab(n), ba(n);
        vector<pair<int, int>> p;
        for (int i = 0; i < n; i ++) {
                int a, b;
                scanf("%d%d", &a, &b);
                p.emplace_back(a, b);
                ab[a].insert(b);
                ba[b].insert(a);
        }
        if (p[0].first != 0 || p[1].second != 0) ng();
        if (p[0].second != p[1].first) ng();
        for (int i = 2; i < n; i ++) {
                int a, b;
                tie(a, b) = p[i];
                cerr << a << ' ' << b << endl;
                if (a == 0 || b == 0) ng();
                if (ab[a - 1].count(b + 1) == 0 && ab[a - 1].count(b) == 0 && ab[a - 1].count(b - 1) == 0) ng();
                if (ba[b - 1].count(a + 1) == 0 && ba[b - 1].count(a) == 0 && ba[b - 1].count(a - 1) == 0) ng();
        }
        assert(false);

        return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:20:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &n);
                        ^
./Main.cpp:25:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
                 scanf("%d%d", &a, &b);
                                      ^

Judge Result