【437】Binary search algorithm，二分搜索算法

Complexity: O(log(n))

Ref: Binary search algorithm or 二分搜索算法

Ref: C 版本 while 循环

C Language scripts by McDelfino:

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#include <stdio.h> #include <stdlib.h>   int getIndex(int* arr, int length, int num);   int main() {     int arr[100];           for (int i = 0; i < 100; i++) {         arr[i] = i + 1;     }           for (int i = 1; i <= 100; i++) {         printf("num = %d, find index = %d.\n", i, getIndex(arr, 100, i));     }       return 0; }   int getIndex(int* arr, int length, int num) {     int min = 0;     int max = length - 1;     int count = 0;     while (1) {         int avg = (min + max)/2;         count++;         if (arr[avg] < num) min = avg + 1;         else if (arr[avg] > num) max = avg - 1;         else {             printf("-----count = %d-----\t", count);             return avg;         }     } }