基础二分法在数据报告中的应用与优化

#include
#include 
#include
#define MAX 100000+100
using namespace std;
int erfen(int *arr, int left, int right, int target)
{
    while (left <= right)
    {
        int mid = (left + right) >> 1;
        if (arr[mid]>target)
            right = mid - 1;
        else
            left = mid + 1;
    }
    return right;                //当left=right的时候，此时比target小的值已确定,所以arr[mid]比target小,left+1,跳出循环,此时right代表的还是mid,即为所求
}

int main()
{
    int n, m;
    int a[MAX], q[MAX];
    while (scanf("%d %d", &n, &m) != EOF)
    {
        memset(a, 0, sizeof(a));
        memset(q, 0, sizeof(q));
        for (int i = 0; i "%d", &a[i]);
        sort(a, a + n);
        for (int j = 0; j "%d", &q[j]);
        for (int k = 0; k )
        {
            int c = q[k];
            if (c >= a[n - 1])
                printf("%d", a[n - 1]);
            else if (c <= a[0])
                printf("%d", a[0]);
            else
                printf("%d", a[erfen(a, 0, n, c)]);         //直接二分查找，查找小于target的最大数的坐标
            if (k != m - 1) printf(" ");
        }
        printf("\n");
    }
    return 0;
}