Submission #666538

#	Time	Username	Problem	Language	Result	Execution time	Memory
666538		AmirH	Robots (APIO13_robots)	C++14	0 / 100	1 ms	340 KiB

robots

#include<iostream>
#include<algorithm>
#include<math.h>
#include<vector>
#include<bitset>
#include<queue>
#include<queue>
#include<deque>
#include<set>
#include<map>
#include<unordered_map>
#include<list>
#include<utility>
#include<stack>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <ll, ll> pll;
typedef pair <int, int> pii;
#define cl clear
#define F  first
#define S  second
#define pb push_back
#define Sz(x) int((x).size())
#define all(x) (x).begin(), (x).end()
#define faster ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
const int MAX_N = 5e2 + 10;
const ll INF = 1e18;
const int inf = 1e9;
// void free() {
//     #ifndef ONLINE_JUDGE
//         freopen("input.txt", "r", stdin);
//         freopen("output.txt", "w", stdout);
//     #endif
// }
int n, w, h;
char ch[MAX_N][MAX_N];
set<int> sat[MAX_N], sot[MAX_N];
vector<int> adj[MAX_N];

int bfs(int st, int ft) {
    int height[MAX_N];
    bool mark[MAX_N];
    for(int i = 1; i <= h * w; i++)
        height[i] = inf, mark[i] = false;
    queue<int> q;
    q.push(st);
    mark[st] = true;
    height[st] = 0;
    while(q.size()) {
        int x = q.front();
        //cout << x << " " << height[x] << '\n';
        q.pop();
        for(auto i : adj[x])
            if(!mark[i]) {
                mark[i] = true;
                q.push(i);
                height[i] = height[x] + 1;
            }
    }
    return height[ft];
}
int get(int x, int y) {
    return (x - 1) * w + y;
}
void find(int x, int y) {
    int rast = *sat[x].upper_bound(y) - 1;
    int chap = *(--sat[x].upper_bound(y)) + 1;
    int paiin = *(sot[y].upper_bound(x)) - 1;
    int bala = *(--sot[y].upper_bound(x)) + 1;
    if(rast != y) {
        adj[get(x, y)].pb(get(x, rast));
    }
    if(chap != y) {
        adj[get(x, y)].pb(get(x, chap));
    }
    if(paiin != x) {
        adj[get(x, y)].pb(get(paiin, y));
    }
    if(bala != x) {
        adj[get(x, y)].pb(get(bala, y));
    }
}
int main() {
    faster; //free();
    cin >> n >> w >> h;
    for(int i = 1; i <= h; i++)
        sat[i].insert(0), sat[i].insert(w + 1);
    for(int i = 1; i <= w; i++)
        sot[i].insert(0), sot[i].insert(h + 1);
    for(int i = 1; i <= h; i++){
        for(int j = 1; j <= w; j++) {
            cin >> ch[i][j];
            if(ch[i][j] == 'x') {
                sat[i].insert(j);
                sot[j].insert(i);
            }
        }
    }
    int st, ft;
    for(int i = 1; i <= h; i++) {
        for(int j = 1; j <= w; j++) {
            if(ch[i][j] != 'x')
                find(i, j);
            if(ch[i][j] == '1')
                st = get(i, j);
            if(ch[i][j] == '2')
                ft = get(i, j);
        }
    }
    // for(int i = 1; i <= h; i++) {
    //     for(int j = 1; j <= w; j++) {
    //         cout << "!! " << i << " " << j << '\n';
    //         for(auto k : adj[get(i, j)])
    //             cout << k << " ";
    //         cout << '\n';
    //     }
    // }
    int res = min(bfs(st, ft), bfs(ft, st));
    if(res == inf)
        cout << -1;
    else
        cout << res;
}

Compilation message (stderr)

robots.cpp: In function 'int main()':
robots.cpp:119:22: warning: 'ft' may be used uninitialized in this function [-Wmaybe-uninitialized]
  119 |     int res = min(bfs(st, ft), bfs(ft, st));
      |                   ~~~^~~~~~~~
robots.cpp:119:22: warning: 'st' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 40