50 lines
1.3 KiB
C
50 lines
1.3 KiB
C
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#include<stdio.h>
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void Search(int a[], int n, int x, int *i, int *j) {
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int start = 0, end = n - 1;
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*i = -1;
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*j = -1;
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while (start <= end) {
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int mid = start + (end - start) / 2;
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if (a[mid] == x) {
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*i = mid; // 找到目标元素
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*j = mid; // 初始化 *j
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// 向左查找相同元素
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while (*i > 0 && a[*i - 1] == x) {
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(*i)--;
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}
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// 向右查找相同元素
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while (*j < n - 1 && a[*j + 1] == x) {
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(*j)++;
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}
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return;
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} else if (a[mid] < x) {
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start = mid + 1;
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*i = mid; // 可能是小于 x 的最大元素
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} else {
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end = mid - 1;
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*j = mid; // 可能是大于 x 的最小元素
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}
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}
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}
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int main() {
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int a[] = {2, 4, 6, 8, 9, 10, 12, 13};
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int x = 7;
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int n = sizeof(a) / sizeof(a[0]);
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int i, j;
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Search(a, n, x, &i, &j);
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if (i == -1 && j == -1) {
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printf("未找到%d的信息\n", x);
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} else if (i == j) {
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printf("目标元素%d位于%d\n", x, i);
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} else {
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printf("未找到目标元素%d的值\n", x);
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printf("小于%d的最大元素位置%d\n", x, i);
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printf("大于%d的最小元素位置%d\n", x, j);
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}
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}
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