結果

問題 No.1120 Strange Teacher
ユーザー Lê Hoàng NgôLê Hoàng Ngô
提出日時 2024-06-29 10:49:43
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 21 ms / 1,000 ms
コード長 2,558 bytes
コンパイル時間 1,426 ms
コンパイル使用メモリ 169,564 KB
実行使用メモリ 5,376 KB
最終ジャッジ日時 2024-06-29 10:49:47
合計ジャッジ時間 2,894 ms
ジャッジサーバーID
(参考情報)
judge5 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 27
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define all(x) x.begin(),x.end()
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define rep_r(i,a,b) for(int i=a;i>=b;i--)
#define each(a,x) for (auto& x : a)
using pi = pair<int,int>;
using pl = pair<ll,ll>;
using vi = vector<int>;
using vl = vector<ll>;
#define sz(x) int(x.size())
#define so(x) sort(all(x))
#define so_r(x) sort(all(x),greater<int>())
#define lb lower_bound
#define ub upper_bound
const char nl = '\n';
int dx[4] = {1,-1,0,0};
int dy[4] = {0,0,1,-1};
int bit_cnt(int x){
return __builtin_popcount(x);
}
ll bex(ll a, ll b, ll mod = 1e9 + 7){ll res = 1LL; while(b){ if (b&1) res = res * a % mod; a = a * a % mod; b >>= 1;} return res;}
template<class t,class u> bool chmax(t&a,u b){if(a<b){a=b;return true;}else return false;}
template<class t,class u> bool chmin(t&a,u b){if(b<a){a=b;return true;}else return false;}
const int MOD = 998244353;
const int N = 5e5 + 5;
const ll INF = 1e16;
// https://yukicoder.me/problems/no/1120
// Brief: N students, real points are A1, A2, ... AN
// but teacher wants to change to B1, B2, ... BN
// in each operation, teacher can increase 1 point for one student but decrease all other students 1 point
// find out minimum operations to achieve that, if impossible print -1
int n;
int a[N], b[N];
void solve(){
cin >> n;
rep(i,1,n) cin >> a[i];
rep(i,1,n) cin >> b[i];
ll dif = 0;
rep(i,1,n) dif+=a[i]-b[i];
// each operation will make total points decrease n-2
// => dif % (n-2) == 0
// and dif > 0
// special case is n == 2
// => dif == 0
if (n == 2){
if (dif != 0) cout << -1 << nl;
else cout << abs(a[1] - b[1]) << nl;
return;
}
if (dif % (n-2) != 0 || dif < 0){
cout << -1 << nl;
return;
}
ll operations = dif / (n-2); // number of operations will be used
// add[i] is the number of operations teacher use for increasing point for student[i]
// b[i] = a[i] - operations + 2 * add[i]
vl add(n+1);
rep(i,1,n){
ll tmp = b[i] - a[i] + operations;
if (tmp % 2 == 1 || tmp < 0) {
cout << -1 << nl;
return;
}
add[i] = tmp / 2;
}
ll tot = operations;
rep(i,1,n){
tot -= add[i];
}
if (tot != 0) {
cout << -1 << nl;
} else {
cout << operations << nl;
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t = 1;
// cin >> t;
while (t--){
solve();
}
}
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