UVa 11636

题目

https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=2683

题意

原来有1个，每次可以任选数量成倍增长，问要操作多少次到n

思路

明显，先扩增到最大数位maxDigit，比如10，先扩增到8，然后再选择n - maxDigit扩增即可。因而结果为log2(n)

代码

#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <tuple>
#define LOCAL_DEBUG
using namespace std;
typedef pair<int, int> MyPair;

int cntDigit(int n) {
    int ans = 0;
    int x = 1;
    while (n > x) {
        ans++;
        x <<= 1;
    }
    return ans;
}

int main() {
#ifdef LOCAL_DEBUG
    freopen("C:\Users\Iris\source\repos\ACM\ACM\input.txt", "r", stdin);
    //freopen("C:\Users\Iris\source\repos\ACM\ACM\output.txt", "w", stdout);
#endif // LOCAL_DEBUG
    int n;
    for (int ti = 1; scanf("%d", &n) == 1 && n > 0; ti++) {
        printf("Case %d: %d
", ti, cntDigit(n));
    }

    return 0;
}