简单二分法查找

C

#include "stdio.h"
#include "stdlib.h"
#include "math.h"
#include "string.h"

unsigned int Search(char* list, int len, int num)
{
  
  int min, max, mid_index;
  min = 0;
  max = len - 1;
  mid_index = (min + max) / 2;
  printf("min=%d, max=%d, mid_index=%d\r\n",min, max, mid_index);
  if (list[min] == num)
  {
    printf("Find: index=%d, value=%d\r\n", min, list[min]);
    return min;
  }
  else if (list[max] == num)
  {
    printf("Find: index=%d, value=%d\r\n", max, list[max]);
    return max;
  }
  while (true)
  {
    if (list[mid_index] == num)
    {
      printf(">> Find: index=%d, value=%d\r\n", mid_index, list[mid_index]);
      return mid_index;
    }
    else if (list[mid_index] > num)
    {
      printf(">> 大了 index=%d, value=%d\r\n", mid_index, list[mid_index]);
      min = min;
      max = mid_index;
      mid_index = (min + max) / 2;
    }
    else
    {
      printf(">> 小了 index=%d, value=%d\r\n", mid_index, list[mid_index]);
      min = mid_index;
      max = max;
      mid_index = (min + max) / 2;
    }
  }
}

int main()
{
  char list[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
  int len = sizeof(list) / sizeof(char);
  Search(list, len, 8);
  return 0;
}

Python

def binarySearch(arr, val):
    head = 0
    end = len(arr)
    mid = (head+end) // 2
    if val > arr[end-1] or val < arr[head]:
        print("No!")
        return
    while 1:
        print(head, mid, end)
        if val == arr[mid]:
            print("Find!", arr[mid])
            break
        elif val < arr[mid]:
            head = head
            end = mid
            mid = (head+end) // 2
        elif val > arr[mid]:
            head = mid
            end = end
            mid = (head + end) // 2



arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
binarySearch(arr, 10)