ZOJ-3162-To Go or Not to Go

来源：互联网发布：数据库实用教程答案编辑：程序博客网时间：2024/06/08 04:29

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<span style="font-size:18px;"># include <cstdio># include <cstring># include <iostream>using namespace std;double dp[30][2];void init(){    memset(dp,0,sizeof(dp));    for(int i = 1;i < 30;i++){        dp[i][1] = dp[i-1][1] + dp[i-1][0] + (1<<i-1);        dp[i][0] = dp[i-1][1] + dp[i-1][0];    }}double fun(int n){    int cnt = 0;double sum = 0;    for(int i = 29;i >= 0;i--){        if(n &(1<<i)){            sum += dp[i+1][0];            sum += (double)(1<<i) * cnt;            cnt++;        }    }    return sum + cnt;}double calc(int a,int b){    int bit1,bit2;    double cnt=b-a+1,sum=0;    for(int i=29;i>=0;i--){        if(a&(1<<i)){            bit1=i;            break;        }    }    for(int i=29;i>=0;i--){        if(b&(1<<i)){            bit2=i;            break;        }    }    if(bit2-bit1==0){        double num=fun(b)-fun(a-1);        sum = num/(bit1+1);    }    else{        int x = (1<<(bit1+1)) - 1;        double num=fun(x) - fun(a-1);        sum = num/(bit1+1);        x = (1<<bit2);        num = fun(b)-fun(x) + 1;        sum += num/(bit2+1);    }    for(int i=bit1+2;i<=bit2;i++)    sum+=dp[i][1]/i;    return sum/cnt;}int main(){    int t;    init();    scanf("%d",&t);    while(t--){        int a,b;        scanf("%d%d",&a,&b);        printf("%.6lf\n",calc(a,b));    }    return 0;}</span>

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