[UVa 11384]Help is needed for Dexter

题解

我们对于$n$，保留$lfloor {n over 2} floor$，以上的部分减去$lceil {n over 2} ceil$这样每次将区间缩小$1 over 2$，保证最优解。

 1 //It is made by Awson on 2017.9.16
 2 #include <map>
 3 #include <set>
 4 #include <cmath>
 5 #include <ctime>
 6 #include <queue>
 7 #include <stack>
 8 #include <cstdio>
 9 #include <string>
10 #include <vector>
11 #include <cstdlib>
12 #include <cstring>
13 #include <iostream>
14 #include <algorithm>
15 #define LL long long
16 #define Max(a, b) ((a) > (b) ? (a) : (b))
17 #define Min(a, b) ((a) < (b) ? (a) : (b))
18 #define Abs(a) ((a) < 0 ? (-(a)) : (a))
19 using namespace std;
20 
21 int n;
22 
23 int f(int n) {
24     return n != 1 ? f(n/2)+1 : 1;
25 }
26 void work(int n) {
27     printf("%d
", f(n));
28 }
29 int main() {
30     while (~scanf("%d", &n))
31         work(n);
32     return 0;
33 }