Submission #3713498

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Source Code Expand

#include<bits/stdc++.h>

using namespace std;

const int INF = 1 << 29;

int dp[500001][27];
int nxt[21][500001];

int main() {
  string s;
  cin >> s;
  for(auto &c : s) c -= 'a';

  fill_n(*dp, 500001 * 27, INF);
  for(int i = (int) s.size() - 1; i >= 0; i--) {
    dp[i][s[i]] = i + 1;
    for(int j = s[i] + 1; j <= 26; j++) {
      if(dp[i][j - 1] == INF) break;
      dp[i][j] = dp[dp[i][j - 1]][j - 1];
    }
    if(dp[i][26] != INF) {
      for(int j = 0; j < s[i]; j++) dp[i][j] = dp[dp[i][26]][j];
    }
  }

  fill_n(*nxt, 21 * 500001, INF);
  for(int i = 0; i < s.size(); i++) {
    nxt[0][i] = dp[i][26];
  }
  for(int i = 1; i < 21; i++) {
    for(int j = 0; j < s.size(); j++) {
      if(nxt[i - 1][j] == INF) continue;
      nxt[i][j] = nxt[i - 1][nxt[i - 1][j]];
    }
  }

  int Q;
  cin >> Q;
  while(Q--) {
    int L, R;
    cin >> L >> R;
    --L;
    int pos = L;
    for(int i = 20; i >= 0; i--) {
      if(nxt[i][pos] <= R) pos = nxt[i][pos];
    }
    if(pos == R) cout << "Yes\n";
    else cout << "No\n";
  }

}

Submission Info

Judge Result