2024.10.29

CF1986E.cpp

@@ -0,0 +1,95 @@
+#include<bits/stdc++.h>
+using namespace std;
+typedef long long LL ;
+typedef pair<int,int> pii;
+const int N = 2e5+50 , mod = 1e9+7;
+
+LL n , m , q , k ,ans ;
+LL a[N] , l[N] , r[N]  ;
+map<LL, vector<LL> > mp ;
+void AC() {
+    cin >> n >> k ;
+    mp.clear() ;
+    for (int i = 1; i <= n ; i++ ) {
+        cin >> q ;
+        mp[ (q%k) ].push_back(q) ;
+    }
+    bool ji = false , fg = false ;
+    ans= 0 ;
+    for (auto tmp : mp) {
+        sort(tmp.second.begin() , tmp.second.end()) ;
+
+        int sz = tmp.second.size() ;
+        //cout << tmp.first << " " << sz << '\n';
+        if (sz & 1) {
+            if ( n & 1) {
+                if (!ji) { ji = true ; }
+                else {
+                    fg = true ;
+                    break;
+                }
+            } else {
+                fg = true ;
+                break;
+            }
+        }
+        LL sum1 = 0  ;
+        for (int j = 0 ; j + 1 < sz ; j += 2 ) {
+            sum1 += ( tmp.second[j+1] - tmp.second[j] ) / k ;
+        }
+
+        if (sz & 1) {
+            LL mn = LONG_LONG_MAX ;
+            a[0] = l[1]  = r[sz-1] = 0 ;
+            for (int j = 1 ; j < sz ; j ++ ) {
+                a[j] = (tmp.second[j] - tmp.second[j-1]) / k ;
+            }
+            for (int j = 1 ; j <= sz-1 ; j+=2) {
+                if (j == 1) l[j] = a[j] ;
+                else l[j] = l[j-2] + a[j] ;
+            }
+            for (int j = sz - 1; j >= 1 ; j -= 2) {
+                if (j == sz - 1) r[j] = a[j] ;
+                else r[j] = r[j+2] + a[j] ;
+            }
+            for (int j = 1 ; j < sz ; j++ ) {
+                LL tp = 0 ;
+                if (j & 1) {
+                    if (j != 1) tp += l[j-2] ;
+                    tp += r[j+1] ;
+                } else {
+                    tp += l[j-1] ;
+                    if (j != sz - 1) tp += r[j+2] ;
+                }
+                mn = min(mn , tp) ;
+            }
+            if (sz == 1) {
+                mn = 0 ;
+            }
+            //mn = min({mn,sum1,sum2}) ;
+            ans += mn ;
+        } else {
+            ans += sum1;
+        }
+
+
+//        cout << tmp.first << "   %  " << sz << " " << ans << '\n';
+//        for (auto v : tmp.second) {
+//            cout << v << " " ;
+//        }
+//        cout << '\n';
+    }
+    if (fg) cout << "-1\n";
+    else cout << ans << '\n';
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);cout.tie(nullptr);
+    int T = 1 ;
+    cin >> T ;
+    while (T--) {
+        AC();
+    }
+    return 0;
+}