Topic links: http://codeforces.com/contest/1165/problem/E
Meaning of the questions:
Change the order of the array B so that the minimum
We can put a [i] * (i + 1) * (n - i) can be processed to a predetermined value, and then sorted in descending order from small to large array b is multiplied is the answer
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <iostream> #include <cstdio> #include <algorithm> #include <cstring> #include <map> #include <set> #include <vector> #include <string> #include <cmath> #include <queue> #define rep(i, s, e) for(int i = s; i < e; ++i) #define lson l, m, rt << 1 #define rson m + 1, r, rt << 1 | 1 #define P pair<int, int> #define INF 0x3f3f3f3f #define Mod 998244353 using namespace std; typedef long long ll; static const int N = 305; static const int MAX_N = 2e5 + 5; ll a[MAX_N], b[MAX_N]; void solve(){ // freopen("input.txt", "r", stdin); // freopen("output.txt", "w", stdout); //ios::sync_with_stdio(false); int n; while(scanf("%d", &n) != EOF){ for(int i = 0; i < n; ++i){ V LL; Scanf ( " % I64d " , & V); A [I] = V * (I + . 1 ) * (n-- I); // this is not the first modulo, or later ordered greedy strategy will be a problem } for ( int I = 0 ; I <n-; I ++) Scanf ( " % I64d " , & B [I]); Sort (A, A + n-, Greater <LL> ()); Sort (B, B + n-); LL ANS = 0 ; for ( int I = 0; i < n; ++i) ans = (ans + (a[i] % Mod) * b[i]) % Mod; printf("%I64d\n", ans); } } int main() { solve(); return 0; }