[20251127] BOJ / P3 / 認証レベル / 권혁준

khj20006/202511/27 BOJ P3 認証レベル.md

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+```cpp
+#include <bits/stdc++.h>
+using namespace std;
+
+const int dx[4] = {1,0,-1,0};
+const int dy[4] = {0,1,0,-1};
+
+int R;
+
+vector<pair<int, int>> office() {
+    int N, M, X, Y;
+    cin>>M>>N>>Y>>X;
+    Y--, X--;
+
+    int root[250000]{};
+    int cnt[250000]{};
+    iota(root, root+N*M, 0);
+    fill(cnt, cnt+N*M, 1);
+    function<int(int)> find = [&](int x) -> int { return x == root[x] ? x : root[x] = find(root[x]); };
+
+    bitset<250000> vis;
+    vis[X*M+Y] = 1;
+
+    vector<tuple<int, int, int>> infos;
+    for(int i=0;i<N;i++) for(int j=0;j<M;j++) {
+        int a;
+        cin>>a;
+        infos.emplace_back(a,i,j);
+    }
+
+    sort(infos.begin(), infos.end());
+    vector<pair<int, int>> events;
+    for(int i=0;i<infos.size();) {
+        auto [cc,aa,bb] = infos[i];
+        int j = i;
+        while(j<infos.size() && get<0>(infos[j]) == cc) {
+            auto [c,a,b] = infos[j];
+            vis[a*M+b] = 1;
+            for(int k=0;k<4;k++) {
+                int aa = a+dx[k], bb = b+dy[k];
+                if(aa<0 || aa>=N || bb<0 || bb>=M || !vis[aa*M+bb]) continue;
+                int x = find(a*M+b), y = find(aa*M+bb);
+                if(x == y) continue;
+                cnt[y] += cnt[x];
+                root[x] = y;
+            }
+            j++;
+        }
+        i = j;
+        events.emplace_back(cc, cnt[find(X*M+Y)]);
+    }
+
+    return events;
+}
+
+int main(){
+    cin.tie(0)->sync_with_stdio(0);
+
+    cin>>R;
+    vector<pair<int, int>> res1 = office();
+    vector<pair<int, int>> res2 = office();
+
+    int ans = 2e9 + 1;
+    for(auto [c,v] : res1) if(v >= R) {
+        ans = min(ans, c);
+        break;
+    }
+    for(auto [c,v] : res2) if(v >= R) {
+        ans = min(ans, c);
+        break;
+    }
+    for(int i=0,j=res2.size()-1;i<res1.size();i++) {
+        if(res1[i].second + res2[j].second >= R) {
+            while(j>=0 && res1[i].second + res2[j].second >= R) j--;
+            j++;
+        }
+        if(res1[i].second + res2[j].second >= R) {
+            ans = min(ans, res1[i].first + res2[j].first);
+        }
+    }
+    cout<<ans;
+
+}
+```