
/*
线性表递增有序存放,设计一算法,用最少的时间查找值为x的元素,
若找到则将其与后续元素位置相交换,否则,插入使其仍然有序
分析:
题目告知这是一个递增有序表,要使时间最少,我们可以采取折半查找的方式,这样比顺序查找省时
*/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int findAndExchange(int* arr, int n, int len) {//返回数组长度
int low = 0, high = len, middle;
while (low <= high && (middle = (low + high) / 2)) {
if (n == arr[middle])break;
if (n < arr[middle]) {
high = middle - 1;
}
else {
low = middle + 1;
}
}
if (low > high) {//未找到,插入
int i;
for (i = len - 1; i > high; i--) {//元素所在位置及其之后的元素后移
*(arr + i + 1) = *(arr + i);
}
*(arr + i + 1) = n;
return len + 1;
}
else {//找到,对调
int tmp = *(arr + middle);
*(arr + middle) = *(arr + middle + 1);
*(arr + middle + 1) = tmp;
return len;
}
}
int main() {
int arr[10] = { 1,3,5,6,9,12,45,78 };
int n, len;
printf("请输入你要查找的元素,n=");
scanf("%d", &n);
len = findAndExchange(arr, n, 8);
for (int i = 0; i < len; i++) printf("%d ", *(arr + i));
return 0;
}