HDU5802-windows 10-dfs+贪心

音量减的时候，分两种，一种是减到大于目标Ｍ，另一种是减到小于Ｍ，停顿的时候可以减少最后往上加的次数，小于０的时候变成０

然后比一下这两种的最小值。

/*--------------------------------------------------------------------------------------*/
#include <algorithm>
#include <iostream>
#include <cstring>
#include <ctype.h>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <string>
#include <queue>
#include <stack>
#include <cmath>
#include <set>
#include <map>

//debug function for a N*M array
#define debug_map(N,M,G) printf("
");for(int i=0;i<(N);i++)
{for(int j=0;j<(M);j++){
printf("%d",G[i][j]);}printf("
");}
//debug function for int,float,double,etc.
#define debug_var(X) cout<<#X"="<<X<<endl;
#define LL long long
const int INF = 0x3f3f3f3f;
const int LLINF = 0x3f3f3f3f3f3f3f3f;
/*--------------------------------------------------------------------------------------*/
using namespace std;

LL N,M,ans;
int T;

LL sum(int x) {return (1LL<<x) - 1LL;}

LL dfs(LL cur,LL cnt,int stop)
{
    //printf("cur:%d cnt:%d
",cur,cnt);
    if(cur == M) return cnt;
    int i = 0;
    while(cur-sum(i) > M) i++;

    if(cur -sum(i) == M ) return cnt + i;
    LL up =  M - max(0LL,cur-sum(i) );
    LL res = i + max(0LL,up-stop);
    return min(cnt+res , dfs(cur-sum(i-1) , cnt + i,stop+1));
}

int main()
{
    scanf("%d",&T);
    while(T--)
    {
        ans = LLINF;
        scanf("%I64d%I64d",&N,&M);
        if(N <= M)
        {
            printf("%I64d
",M-N);
            continue;
        }

        printf("%I64d
",dfs(N,0,0));
    }
}