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50 lines
1.0 KiB
C++
50 lines
1.0 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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int t, k;
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long long x, ans;
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inline long long calc(long long d) {
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return (d + 1) * d / 2;
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}
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inline long long calc2(long long d) {
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return (k * 2 - d + 1) * d / 2;
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}
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int main() {
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cin >> t;
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while (t--) {
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cin >> k >> x;
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long long l = 0, r = k;
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while (l < r) {
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int mid = l + r + 1 >> 1;
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if (calc(mid) <= x) {
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l = mid;
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} else {
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r = mid - 1;
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}
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}
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if (r < k) {
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ans = r + (calc(r) < x);
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cout << min(ans, k * 2ll - 1) << endl;
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continue;
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}
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x -= (k - 1ll) * k / 2ll;
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l = 0;
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r = k;
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while (l < r) {
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int mid = l + r + 1 >> 1;
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if (calc2(mid) <= x) {
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l = mid;
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} else {
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r = mid - 1;
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}
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}
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ans = (r + k - 1 + (calc2(r) < x));
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cout << min(ans, k * 2ll - 1) << endl;
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}
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return 0;
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}
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