light OJ 1282 - Leading and Trailing 数学 || double技巧

http://lightoj.com/volume_showproblem.php?problem=1282

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <assert.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;


#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <bitset>


//int calc(LL a, LL b, int k) { //a^b的前k + 1位
//    double res = b * log10(a * 1.0) - (LL)(b * log10(a * 1.0)); //小数部分
//    return (int)pow(10.0, k + res);
//}
int calc(double a, LL b, int k) {
    double ans = 1, base = a;
    while (b) {
        if (b & 1) {
            ans = ans * base;
        }
        b >>= 1;
        base = base * base;
        while (ans >= 1000) ans /= 10; //保留前3位
        while (base >= 1000) base /= 10;
    }
    return (int)ans;
}
int quick_pow(LL a, LL b, int MOD) {
    LL ans = 1, base = a % MOD;
    while (b) {
        if (b & 1) ans = ans * base % MOD;
        b >>= 1;
        base = base * base % MOD;
    }
    return ans;
}
void work() {
    LL a, b;
    cin >> a >> b;
    static int f = 0;
    printf("Case %d: %d %03d\n", ++f, calc(a, b, 3), quick_pow(a, b, 1000));
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    int t;
    scanf("%d", &t);
    while (t--) work();
    return 0;
}