Submission #31951

#	Time	Username	Problem	Language	Result	Execution time	Memory
31951		minhtung0404	물병 (JOI14_bottle)	C++14	100 / 100	3196 ms	156400 KiB

bottle

#include<bits/stdc++.h>
const int N = 2e5 + 5;
const int inf = 1e9;
using namespace std;

typedef pair <int, int> ii;
typedef pair <int, ii> iii;

vector <ii> adj[N];
priority_queue <iii, vector <iii>, greater <iii> > pq;

int n, m, p, q, x[N], y[N], dx[] = {-1, 0, 1, 0}, dy[] = {0, -1, 0, 1}, lev[N], d[20][N], M[20][N];
char s[2005][2005];
int dd[2005][2005], ee[2005][2005];

struct {
    int pset[N];
    void init(int n) {for (int i = 1; i <= n; i++) pset[i] = i;}
    int findset(int i) {return ((pset[i] == i) ? i : pset[i] = findset(pset[i]));}
    void unionset(int i, int j){
        if (findset(i) == findset(j)) return ;
        pset[findset(i)] = findset(j);
    }
} dsu;

void bfs(){
    queue <ii> mq;
    for (int i = 1; i <= p; i++){
        mq.push(ii(x[i], y[i]));
        dd[x[i]][y[i]] = 1; ee[x[i]][y[i]] = i;
    }
    while (mq.size()){
        int xx = mq.front().first, yy = mq.front().second; mq.pop();
        for (int i = 0; i < 4; i++){
            int xxx = xx + dx[i], yyy = yy + dy[i];
            if (xxx < 0 || xxx >= n || yyy < 0 || yyy >= m) continue;
            if (s[xxx][yyy] == '#') continue;
            if (dd[xxx][yyy]){
                if (ee[xx][yy] != ee[xxx][yyy]) pq.push(iii(dd[xx][yy]+dd[xxx][yyy]-2, ii(ee[xxx][yyy], ee[xx][yy])));
                continue;
            }
            dd[xxx][yyy] = dd[xx][yy] + 1; ee[xxx][yyy] = ee[xx][yy];
            mq.push(ii(xxx, yyy));
        }
    }
}

void dfs(int u, int p){
    for (int i = 0; i < int(adj[u].size()); i++){
        int v = adj[u][i].first, cost = adj[u][i].second;
        if (v == p) continue;
        lev[v] = lev[u] + 1;
        d[0][v] = u; M[0][v] = cost;
        dfs(v, u);
    }
}

int lca(int u, int v){
    int ans = 0;
    for (int i = 19; i >= 0; i--) if (lev[d[i][u]] >= lev[v]) ans = max(ans, M[i][u]), u = d[i][u];
    for (int i = 19; i >= 0; i--) if (lev[d[i][v]] >= lev[u]) ans = max(ans, M[i][v]), v = d[i][v];
    for (int i = 19; i >= 0; i--) {
        if (d[i][u] != d[i][v]){
            ans = max(ans, M[i][u]); ans = max(ans, M[i][v]);
            u = d[i][u]; v = d[i][v];
        }
    }
    if (u != v) ans = max(ans, M[0][u]), ans = max(ans, M[0][v]);
    return ans;
}

int main(){
    scanf("%d %d %d %d", &n, &m, &p, &q);
    for (int i = 0; i < n; i++) scanf("%s", &s[i]);
    for (int i = 1; i <= p; i++) {
        scanf("%d %d", &x[i], &y[i]);
        x[i]--; y[i]--;
    }
    bfs(); dsu.init(p);
    while (pq.size()){
        int cost = pq.top().first, u = pq.top().second.first, v = pq.top().second.second; pq.pop();
        if (dsu.findset(u) != dsu.findset(v)) {
            adj[u].push_back(ii(v, cost));
            adj[v].push_back(ii(u, cost));
            dsu.unionset(u, v);
        }
    }
    for (int i = 2; i <= p; i++){
        if (dsu.findset(1) != dsu.findset(i)){
            adj[1].push_back(ii(i, inf));
            adj[i].push_back(ii(1, inf));
            dsu.unionset(1, i);
        }
    }
    dfs(1, 1);
    for (int i = 1; i < 20; i++) for (int j = 1; j <= p; j++) {
        d[i][j] = d[i-1][d[i-1][j]];
        M[i][j] = max(M[i-1][j], M[i-1][d[i-1][j]]);
    }
    while (q--){
        int a, b;
        scanf("%d %d", &a, &b);
        int ans = lca(a, b);
        ans = ((ans == inf) ? -1 : ans);
        printf("%d\n", ans);
    }
}

Compilation message (stderr)

bottle.cpp: In function 'int main()':
bottle.cpp:74:50: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[2005]' [-Wformat=]
     for (int i = 0; i < n; i++) scanf("%s", &s[i]);
                                                  ^
bottle.cpp:73:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d %d", &n, &m, &p, &q);
                                         ^
bottle.cpp:74:51: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (int i = 0; i < n; i++) scanf("%s", &s[i]);
                                                   ^
bottle.cpp:76:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &x[i], &y[i]);
                                     ^
bottle.cpp:102:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
                               ^

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30