HDU - 6182 A Math Problem

equation_H發表於2020-10-12

給出一個正整數n,請數數有多少正整數k滿足k的k次方 <=n
本地打表或者通過快速冪均可

#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
ll qpow(ll a,ll n)
{
    ll prot=1;
    while(n){
        if(n&1) prot=prot*a;
        a=a*a;
        n>>=1;
    }
    return prot;
}
int main()
{
    ll n;
    while(scanf("%lld",&n)==1){
            //cout<<qpow(n,n)<<endl;
        int i;
        for(i=1;;i++){
            if(i==16) {
                break;
            }
            if(qpow(i,i)<=n) continue;
            else break;
        }
        printf("%d\n",i-1);
    }
}
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
//const LL modd = 1000000007;
const LL s[] = { 0, 1, 4, 27, 256, 3125, 46656, 823543, 16777216, 387420489, 10000000000, 285311670611, 8916100448256,
 302875106592253, 11112006825558016, 437893890380859375};
int main() {
    LL n;
//    for(LL i = 1 ; i <= 21; i++) {
//        LL t = i;
//        for(LL j = 1; j < i; j++) {
//            t *= i;
//        }
//        printf(" %lld,", t);
//
//    }

    while(cin>>n){
        LL ans = 0;
        for(LL i = 1; i <= 15; i++) {
            if( s[i] <= n ) ans++;
            else break;

        }
        cout << ans << endl;
    }
    return 0;
}

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