C++14 解法, 执行用时: 1ms, 内存消耗: 372KB, 提交时间: 2020-08-20

#include <cstdio>
 
int main()
{
    int n;
    while(scanf("%d", &n) != EOF){
        int b = 1;
        while(b <= n + 1){
            b <<= 1;
        }
        printf("%d\n", (b >> 1) - 1);
    }
    return 0;
}

C 解法, 执行用时: 2ms, 内存消耗: 296KB, 提交时间: 2021-12-11

#include <stdio.h>
#include <assert.h>
int main(void)
{
    int n;
    while(scanf("%d", &n) != EOF)
    {
//         assert(n > 0);
//         assert(n <= 1000);
        
        int idx = 0, scale = 1;
        while(idx+scale <= n)
        {
            idx += scale;
            scale <<= 1;
        }
        printf("%d\n", idx);
    }
    return 0;
}

C 解法, 执行用时: 2ms, 内存消耗: 316KB, 提交时间: 2021-09-16

#include <stdio.h>
#include <math.h>

int main()
{
    int n=0;
    while(scanf("%d",&n) != EOF)
    {
        int m=0;
        int num = pow(2,m)-1;
        while(num < n)
        {
            
            int temp = pow(2,(m+1))-1;
            if(temp >= n)
            {
                printf("%d\n",num);
                break;
            }
            else 
            {
                m++;
                num = temp;
            }
        }
    }
    return 0;
}

C 解法, 执行用时: 2ms, 内存消耗: 316KB, 提交时间: 2021-08-21

#include <stdio.h>
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        int num=0;
        while(n=n/2)
        {
            num=num*2+1;
        }
        printf("%d\n",num);
    }
    return 0;
}

C 解法, 执行用时: 2ms, 内存消耗: 356KB, 提交时间: 2022-05-03

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n = 0;
    while (scanf("%d", &n) != EOF)
    {
      /*  int* arr = (int*)malloc(4 * n);
        if (arr == NULL)
        {
            perror("malloc");
            return 1;
        }*/
        int arr[1000] = { 0 };
        int i = 0;
        int j = 0;
        int temp = n;
        for (i = 0; i <= n; i++)
        {
            arr[i] = i;
        }
        while (1)
        {
            j = 0;
            for (i = 1; i <= temp; i += 2)
            {
                arr[j++] = arr[i];
            }
            temp = j;
            if (temp == 1)
                break;
        }
        printf("%d\n", arr[0]);

        //free(arr);
        //arr = NULL;
    }

    return 0;
}