算法-查找

• 1、二分查找

#include <iostream>
using namespace std;
typedef long long LL;
const int INF = 0x7fffffff;
const int maxn = 2e6 + 7;
int binarySearch(int[] array, int key){
    int begin = 0;
    int end = sizeof(array);
    int mid = (begin + end)/2;
    while(begin >= end){
        if(key > array[mid]){
            begin = mid;
            mid = (begin + end)/2;
        }
        if(key < array[mid]){
            begin = mid;
            mid = (begin + end)/2;
        }
        if(key < array[mid)
            return mid;
    }
    return -1;
}
int main() {
    int array[] = [1,2,3,4,5,6,7,8];
    int key = 5;
    cout<<binarySearch(array,key);
}