Submission #25206

#	Time	Username	Problem	Language	Result	Execution time	Memory
25206		minimario	Senior Postmen (BOI14_postmen)	C++14	55 / 100	119 ms	18048 KiB

postmen

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

#define pb push_back
#define mp make_pair
#define f first
#define s second

#define FOR(i, a, b) for (int i=a; i<b; i++)
#define F0R(i, a) FOR(i, 0, a)

const int MAX = 100005;
const int MAXN = 1000005;
const int MOD = 1000000007;
const int MAGIC = 3;

template <typename T>
std::ostream& operator<< (std::ostream& out, const std::vector<T>& v) {
  if ( !v.empty() ) {
    out << '[';
    std::copy (v.begin(), v.end(), std::ostream_iterator<T>(out, ", "));
    out << "\b\b]";
  }
  return out;
}

int e1[MAXN], e2[MAXN], banned[MAXN]; // edges, and dif the edge is banned
vi g[MAX];

void remove_edges(int u) {
    while (!g[u].empty() && banned[g[u].back()]) {
        g[u].pop_back();
    }
}

int v[MAX];
vector<vi> answer;

void chain(int u) {
    vi ord;
    int st = u;
    while (!g[st].empty()) {
        ord.pb(st);
        int e = g[st].back(); banned[e] = true;
        int from = st, to = e1[e] + e2[e] - from;
        remove_edges(from); remove_edges(to);
        st = to;
    }
    ord.pb(st);
    vi cycle, cur;
    for (int i : ord) {
        cur.pb(i);
        v[i]++;
        if (v[i] >= 2) {
            do {
                v[cur.back()]--;
                cycle.pb(cur.back());
                cur.pop_back();
            } while (cur.back() != i);
            cycle.pb(cycle[0]);
            answer.pb(cycle);
            cycle.clear();
        }
    }
    for (int i : cur) { v[i]--; }
}


int main() {
    int num = 0; // number of edge
    int n, m; scanf("%d %d", &n, &m);
    F0R(i, m) {
        int a, b; scanf("%d %d", &a, &b);
        e1[i] = a; e2[i] = b;
        g[a].pb(i); g[b].pb(i); num++;
    }
    FOR(i, 1, n+1) { chain(i); }
    for (vector<int> i : answer) { num -= i.size(); num++; }
    if (num == 0) {
        for (vector<int> i : answer) {
            FOR(moo, 1, i.size()) {
                printf("%d", i[moo]); 
                if (moo == (int) i.size() - 1) { printf("\n"); }
                else { printf(" "); }
            }
        }
    }
    else { printf("NIE\n"); }
}

Compilation message (stderr)

postmen.cpp: In function 'int main()':
postmen.cpp:14:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define FOR(i, a, b) for (int i=a; i<b; i++)
postmen.cpp:86:17:
             FOR(moo, 1, i.size()) {
                 ~~~~~~~~~~~~~~~~     
postmen.cpp:86:13: note: in expansion of macro 'FOR'
             FOR(moo, 1, i.size()) {
             ^~~
postmen.cpp:76:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     int n, m; scanf("%d %d", &n, &m);
               ~~~~~^~~~~~~~~~~~~~~~~
postmen.cpp:78:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         int a, b; scanf("%d %d", &a, &b);
                   ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 38 / 38
• Subtask 2: 17 / 17
• Subtask 3: 0 / 45