Submission #51500972

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Source Code Expand

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

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

int digits(ll n) {
    int ret = 0;
    while (n != 0) {
        ++ret;
        n /= 10;
    }
    return ret;
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int TESTS; cin >> TESTS;
    while (TESTS--) {
        ll n; cin >> n;

        ll ans = 1;

        int d = digits(n);
        int yd = (d - 1) / 2 + 1;

        ll a = 100, b = 10;
        for (int i = 2; i <= yd + 1; ++i) {
            if (a - 2 * b <= n) {
                ++ans;
            }

            ans += max(min(a + b - 1, n) - (a - b) + 1, 0LL);
            a *= 100LL;
            b *= 10LL;
        }

        cout << ans << "\n";
    }
}

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