Create 2019-H-B.cpp

Author: tmp-coder

Diff for: kick-start/2019-H-B.cpp

@@ -0,0 +1,81 @@
+#include<bits/stdc++.h>
+#include<bits/extc++.h>
+#define ms(x,v) memset((x),v,sizeof(x))
+#define INF 0x3f3f3f3f
+using namespace std;
+// using namespace __gnu_pbds;
+
+const int MAXN = 100+10;
+typedef long long LL;
+typedef pair<int,bool> PIB;
+
+
+
+void dfs(int u,bool flip,int &cnt,vector<bool>& col,vector<bool>&vis,const vector<vector<PIB>> & G){
+    if(vis[u]){
+        if(col[u] != flip)
+            cnt = INF;
+        return;
+    }   
+    vis[u] = true;
+    col[u] = flip;
+    if(flip)cnt ++ ;
+    for(const auto & e : G[u])
+        dfs(e.first,flip ^ e.second,cnt,col,vis,G);
+}
+
+void solve(){
+    int n;
+    cin >> n;
+    const int offset = 2 *n -2 + n;
+    const int MAX_V = 4 *n - 2;
+    vector<vector<PIB> > G(MAX_V);
+    for(int i=0 ; i<n ; ++i){
+        string s;
+        cin >> s;
+        for(int j=0 ; j<n ; ++j)
+        {
+            int x = i + j;
+            int y = i-j + offset;
+            bool v = (s[j] == '.');
+            G[x].push_back(make_pair(y,v));
+            // cout  << x << " " << y << " "<< v << "\n";
+            G[y].push_back(make_pair(x,v));
+        }
+    }
+
+    vector<bool> vis1(MAX_V,false),vis2(MAX_V,false),col(MAX_V,false);
+    int ans =0;
+
+    for(int i=0 ; i< MAX_V ; ++i){
+        if(vis1[i])
+            continue;
+        int cnt1 = 0,cnt2 = 0;
+        dfs(i,0,cnt1,col,vis1,G);
+        dfs(i,1,cnt2,col,vis2,G);
+
+        ans += min(cnt1,cnt2);
+    }
+    cout << ans << '\n';
+}
+
+
+
+
+
+int main(){
+    ios :: sync_with_stdio(0);
+    cin.tie(0);
+    cout.tie(0);
+    std::cout.precision(10);
+    std::cout.setf( std::ios::fixed, std:: ios::floatfield );
+    int T;
+    cin >> T;
+    // cout << T << '\n';
+    for(int tt =1 ; tt <=T ; ++tt)
+    {
+        cout << "Case #" << tt << ": ";
+        solve();
+    }
+    return 0;
+}