Submission #107259

#	Time	Username	Problem	Language	Result	Execution time	Memory
107259		batmend_kh	Friend (IOI14_friend)	C++14	Compilation error	0 ms	0 KiB

friend

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

struct edge{
    int bg;
    int en;
    int flow;
    edge (int bg, int en, int flow) {
        this -> bg = bg;
        this -> en = en;
        this -> flow = flow;
    }
};

int height, width, n_banks;
vector<edge> edges;
vector<vector<pair<int, int> > > adj;
pair<int, int> parent[6005];

int get_in(int h, int w) {
    return h * width + w;
}
int get_out(int h, int w) {
    return get_in(h, w) + 3000;
}

void make_edge(int bg, int en) {
    edges.push_back(edge(bg, en, 1));
    adj[bg].push_back(make_pair(en, edges.size() - 1));
    adj[en].push_back(make_pair(bg, edges.size() - 1));
}

bool found_path() {
    queue <int> q;
    for (int i = 0; i <= 6001; i++) parent[i] = make_pair(-1, -1);
    q.push(6000);
    parent[6000] = make_pair(0, 0);
    while (!q.empty()) {
        int current = q.front();
        q.pop();
        for (int i = 0; i < adj[current].size(); i++) {
            if (parent[adj[current][i].first] != make_pair(-1, -1)) continue;
            edge x = edges[adj[current][i].second];
            int bg = x.bg;
            int en = x.en;
            if (current == bg && x.flow == 1) {
                parent[en] = make_pair(bg, i);
                q.push(en);
            }
            if (current == en && x.flow == 0) {
                parent[bg] = make_pair(en, i);
                q.push(bg);
            }
        }
    }
    if (parent[6001] == make_pair(-1, -1)) return 0;
    else return 1;
}

int main() {
    int q_;
    cin >> q_;
    while (q_--) {
        cin >> width >> height >> n_banks;
        int answer = 0;
        edges.clear();
        adj = vector<vector<pair<int, int> > > (6005);
        for (int i = 1; i <= height; i++) {
            for (int j = 1; j <= width; j++) {
                make_edge(get_in(i, j), get_out(i, j));
                if (i - 1 > 0) make_edge (get_out(i, j), get_in(i - 1, j));
                if (j - 1 > 0) make_edge (get_out(i, j), get_in(i, j - 1));
                if (i + 1 <= height) make_edge (get_out(i, j), get_in(i + 1, j));
                if (j + 1 <= width) make_edge (get_out(i, j), get_in(i, j + 1));
                if (i - 1 == 0 || j - 1 == 0 || i + 1 > height || j + 1 > width) make_edge (get_out(i, j), 6001);
            } 
        }
        for (int i = 0, x, y; i < n_banks; i++) {
            cin >> x >> y;
            make_edge(6000, get_in(y, x));
        }
        while (found_path()) {
            answer++;
            for (int i = 6001; i != 6000; i = parent[i].first) {
                edges[adj[parent[i].first][parent[i].second].second].flow ^= 1;
            }
        } 
        if (answer == n_banks) cout << "possible" << '\n';
        else cout << "not possible" << '\n';
    }
}

Compilation message (stderr)

friend.cpp: In function 'bool found_path()':
friend.cpp:41:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < adj[current].size(); i++) {
                         ~~^~~~~~~~~~~~~~~~~~~~~
/tmp/ccTP0w6T.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccpl0glA.o:friend.cpp:(.text.startup+0x0): first defined here
/tmp/ccTP0w6T.o: In function `main':
grader.cpp:(.text.startup+0xba): undefined reference to `findSample(int, int*, int*, int*)'
collect2: error: ld returned 1 exit status