// Om Namah Shivaya
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a, b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a, b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
refs:
https://codeforces.com/blog/entry/112664 (cartesian trees => construction and properties)
thought process:
thought cartesian tree can be used
=> read blog
=> understood properties
=> understood from the blog and some comments that it can be constructed in O(n) using stacks
=> realized that montonic stack for calculating nge to left and right is enough (1/0 can be used to represent push/pop respectively)
=> so dont need cartesian tree, just monotonic stack + some way to answer queries using the nge left and nge right values
=> the answer to a query is the leftmost guy with the maximum nge_right value in range [l,r]
*/
const int MOD = 1e9 + 7;
const int N = 4e4 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
#include "floppy.h"
void read_array(int subtask_id, const std::vector<int> &a) {
int n = sz(a);
string bits = "";
stack<int> st;
vector<int> lx(n,0), rx(n,n-1);
rep(i,n){
while(!st.empty() and a[i] > a[st.top()]){
rx[st.top()] = i-1;
st.pop();
bits.pb('0');
}
if(!st.empty()){
lx[i] = st.top()+1;
}
st.push(i);
bits.pb('1');
}
save_to_floppy(bits);
}
template<typename T>
struct sparse_table {
/*============================*/
T merge(T a, T b) {
return max(a,b);
}
/*============================*/
vector<vector<T>> table;
vector<int> bin_log;
int LOG = 0;
sparse_table() {
}
sparse_table(vector<T> &a, int n) {
while ((1 << LOG) <= n) LOG++;
table = vector<vector<T>>(n, vector<T>(LOG));
bin_log = vector<int>(n + 1);
rep(i, n) table[i][0] = a[i];
rep1(j, LOG - 1) {
rep(i, n) {
int jump = 1 << (j - 1);
if (i + jump >= n) {
break;
}
table[i][j] = merge(table[i][j - 1], table[i + jump][j - 1]);
}
}
bin_log[1] = 0;
for (int i = 2; i <= n; ++i) {
bin_log[i] = bin_log[i / 2] + 1;
}
}
T query(int l, int r) {
int len = r - l + 1;
int k = bin_log[len];
T val1 = table[l][k];
T val2 = table[r - (1 << k) + 1][k];
return merge(val1, val2);
}
};
std::vector<int> solve_queries(int subtask_id, int n,
const std::string &bits,
const std::vector<int> &L, const std::vector<int> &R) {
stack<int> st;
vector<int> lx(n,0), rx(n,n-1);
int ptr = 0;
rep(i,n){
while(bits[ptr] == '0'){
rx[st.top()] = i-1;
st.pop();
ptr++;
}
if(!st.empty()){
lx[i] = st.top()+1;
}
st.push(i);
ptr++;
}
vector<pii> b(n);
rep(i,n) b[i] = {rx[i],-i};
sparse_table<pii> sparse(b,n);
int m = sz(L);
vector<int> ans(m);
rep(i,m){
int l = L[i], r = R[i];
ans[i] = -sparse.query(l,r).ss;
// for(int j = l; j <= r; ++j){
// if(lx[j] <= l and rx[j] >= r){
// ans[i] = j;
// }
// }
}
return ans;
}
Compilation message
stub.cpp: In function 'void run2()':
stub.cpp:101:30: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
101 | if (query_answers.size() != M) {
| ~~~~~~~~~~~~~~~~~~~~~^~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
792 KB |
Output is correct |
| 2 |
Correct |
1 ms |
792 KB |
Output is correct |
| 3 |
Correct |
1 ms |
784 KB |
Output is correct |
| 4 |
Correct |
2 ms |
792 KB |
Output is correct |
| 5 |
Correct |
1 ms |
792 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
18 ms |
4076 KB |
Output is correct |
| 2 |
Correct |
18 ms |
4116 KB |
Output is correct |
| 3 |
Correct |
19 ms |
4204 KB |
Output is correct |
| 4 |
Correct |
17 ms |
4124 KB |
Output is correct |
| 5 |
Correct |
18 ms |
4124 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
76 ms |
15372 KB |
Output is correct |
| 2 |
Correct |
76 ms |
15420 KB |
Output is correct |
| 3 |
Correct |
68 ms |
15224 KB |
Output is correct |
| 4 |
Correct |
69 ms |
15400 KB |
Output is correct |
| 5 |
Correct |
69 ms |
15340 KB |
Output is correct |
