索引数组_索引数组indexarray、数组低指针low、数组高指针heigh、索引偏移量d-优快云博客

本文链接：https://blog.youkuaiyun.com/liulicsdn/article/details/41848817

本文介绍了一种通过创建索引数组进行排序的方法，并在此基础上实现了折半查找算法。通过对索引数组进行选择排序，可以保持原有数组不变的同时完成排序操作。随后利用排序后的索引数组进行高效的折半查找。

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<span style="font-size:18px;">// 索引数组
    int array[] = {3, 2, 6, 9, 8, 5, 7, 1, 4};
    int count = sizeof(array) / sizeof(array[0]);
    int indexs[count];
    for (int i = 0; i < count; i++) {
        indexs[i] = i;

    }
//    int flag = 1;
//    for (int i = 0 ; i < count - 1 && 1 == flag; i++) {
//        flag = 0;
//        for (int j = 0; j < count - i - 1; j++) {
//            if (array[indexs[j]] > array[indexs[j + 1]]) {
//                int  temp = indexs[j];
//                indexs[j] = indexs[j + 1];
//                indexs[j + 1] = temp;
//                flag = 1;
//            }
//        }
//    }
    //索引数组 选择排序  
    int minIndex = 0;
    for (int i = 0; i < count - 1; i++) {
        minIndex = i;
        for (int j = minIndex + 1; j  < count; j++) {
            if (array[indexs[minIndex]] > array[indexs[j]]) {
                minIndex = j;
            }
        }
        if (minIndex != i) {
            int temp =indexs[minIndex];
            indexs[minIndex] = indexs[i];
            indexs[i] = temp;
            
        }
    }
    for (int i = 0; i < count; i++) {
        printf("a[%2d] = %2d\n",indexs[i], array[indexs[i]]);
    }
</span>

索引数组：折半查找

<span style="font-size:18px;"> for (int  i = 0 ; i < count; i++) {
        printf("[%d] : %d\n", indexs[i], array[indexs[i]]);
    }
    int start = 0 ,end = count - 1, mid = 0;
    printf("please input  a number\n");
    int target;
    scanf("%d", &target);
    //printf("%d\n", target);
    while (start <= end) {
        mid = (start + end) / 2;
        if (array[indexs[mid]] > target) {
            end = mid - 1;
        } else if (array[indexs[mid]] < target) {
            start = mid + 1;
        } else {
            break;
        }
    }
</span>