math/isqrt.hpp

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• Last update: 2025-04-30 03:58:10+00:00
• Include: #include "math/isqrt.hpp"

Code

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

// floor(sqrt(n)) を返す
long long isqrt(long long n) {
    assert(0 <= n);
    long long re = sqrt(n);
    while ((re + 1) * (re + 1) <= n) re++;
    while (n < re * re) re--;
    return re;
}

#line 2 "math/isqrt.hpp"
#include <bits/stdc++.h>
using namespace std;

// floor(sqrt(n)) を返す
long long isqrt(long long n) {
    assert(0 <= n);
    long long re = sqrt(n);
    while ((re + 1) * (re + 1) <= n) re++;
    while (n < re * re) re--;
    return re;
}

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