Submission #53376415

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Source Code Expand

#include <cmath>
#include <iostream>
#include <vector>
using namespace std;

const int MOD = 998244353;
const int MAX_LEN = 11;  // 1e9までの数の最大桁数

// 長さが l の整数に対して 10^l を計算し、MOD を取る
vector<long long> power_of_ten(MAX_LEN);

void precompute_powers() {
  power_of_ten[0] = 1;
  for (int i = 1; i < MAX_LEN; ++i) {
    power_of_ten[i] = power_of_ten[i - 1] * 10 % MOD;
  }
}

// 整数 x の桁数を返す
int digit_length(long long x) {
  if (x == 0) return 1;
  int length = 0;
  while (x) {
    x /= 10;
    length++;
  }
  return length;
}

int main() {
  int N;
  cin >> N;
  vector<long long> A(N);
  vector<int> len(N);
  vector<vector<long long>> sum(MAX_LEN, vector<long long>(N + 1, 0));

  precompute_powers();

  for (int i = 0; i < N; ++i) {
    cin >> A[i];
    len[i] = digit_length(A[i]);
  }

  // 各桁数の値の合計を求める
  for (int i = 0; i < N; ++i) {
    for (int l = 1; l < MAX_LEN; ++l) {
      sum[l][i + 1] = (sum[l][i] + (A[i] * power_of_ten[l] % MOD)) % MOD;
    }
  }

  long long result = 0;

  // 各ペアの f(A_i, A_j) の合計を計算
  for (int i = 0; i < N; ++i) {
    for (int j = i + 1; j < N; ++j) {
      long long fij = (A[i] * power_of_ten[len[j]] % MOD + A[j]) % MOD;
      result = (result + fij) % MOD;
    }
  }

  cout << result << endl;

  return 0;
}

Submission Info

Judge Result