Submission #401961

#	Time	Username	Problem	Language	Result	Execution time	Memory
401961		rama_pang	Sum Zero (RMI20_sumzero)	C++17	100 / 100	752 ms	12372 KiB

sumzero

#include <bits/stdc++.h>
using namespace std;

const int MAX = 400005;
const int BASE = 32;
const int LOG32 = 4;

int N;
int A[MAX];
int pow32[LOG32];
int dp[MAX][LOG32];

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);

  pow32[0] = 1;
  for (int i = 1; i < LOG32; i++) {
    pow32[i] = BASE * pow32[i - 1];
  }

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

  // dp[i][x] = minimum j, such that [i, j - 1] contains BASE^x valid segments
  { // Compute dp[]
    for (int i = 0; i <= N + 1; i++) {
      for (int j = 0; j < LOG32; j++) {
        dp[i][j] = N + 1;
      }
    }
    long long sum = 0;
    vector<long long> coords;
    coords.emplace_back(sum);
    for (int i = N - 1; i >= 0; i--) {
      sum += A[i];
      coords.emplace_back(sum);
    }
    sort(begin(coords), end(coords));
    coords.resize(unique(begin(coords), end(coords)) - begin(coords));

    sum = 0;
    vector<int> last(coords.size(), N + 1);
    const auto Get = [&](long long x) {
      return lower_bound(begin(coords), end(coords), x) - begin(coords);
    };
    last[Get(sum)] = N;
    for (int i = N - 1; i >= 0; i--) {
      sum += A[i];
      dp[i][0] = last[Get(sum)];
      last[Get(sum)] = i;
    }
    for (int i = N - 2; i >= 0; i--) {
      dp[i][0] = min(dp[i][0], dp[i + 1][0]);
    }
    for (int j = 1; j < LOG32; j++) {
      for (int i = 0; i < N; i++) {
        int x = i;
        for (int k = 0; k < BASE; k++) {
          x = dp[x][j - 1];
        }
        dp[i][j] = x;
      }
    }
  }

  int Q;
  cin >> Q;
  while (Q--) {
    int L, R;
    cin >> L >> R;
    L--;
    int ans = 0;
    int x = LOG32 - 1;
    while (x >= 0) {
      if (dp[L][x] <= R) {
        ans += pow32[x];
        L = dp[L][x];
      } else {
        x--;
      }
    }
    cout << ans << '\n';
  }
  return 0;
}

• Subtask 1: 22 / 22
• Subtask 2: 39 / 39
• Subtask 3: 39 / 39