47 lines
1.3 KiB
Plaintext
47 lines
1.3 KiB
Plaintext
/* file name: binarySearch.c */
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/* 二元搜尋 */
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#include <stdio.h>
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#include <stdlib.h>
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int main()
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{
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int data[10] = {12, 23, 29, 38, 44, 57, 64, 75, 82, 98};
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int i, left = 0, right = 9, mid, cnt = 0, input, ok = 0;
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printf("\n<< Binary search >>\n");
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printf("\n已排序好的資料: ");
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for(i = 0; i < 10; i++)
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printf("%d ", data[i]);
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printf("\n");
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printf("\n請輸入欲找尋的資料: ");
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scanf("%d", &input);
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printf("\nSearching....\n");
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mid = (left + right)/2; /* 鍵值在第M筆 */
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while (left <= right && ok == 0) {
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printf("\n第%2d 次找的資料是: %d!", ++cnt, data[mid]);
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/* 欲搜尋的資料小於鍵值，則資料在鍵值的前面 */
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if(data[mid] > input) {
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right = mid - 1;
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printf("\n ---> 要找的資料小於 %d\n", data[mid]);
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}
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/* 否則資料在鍵值的後面 */
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else {
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if(data[mid] < input) {
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left = mid + 1;
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printf("\n ---> 要找的資料大於 %d\n", data[mid]);
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}
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else {
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printf("\n\n找到了, %d 是在索引 %d 的位置!\n", input, mid);
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ok = 1;
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}
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}
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mid = (left + right)/2;
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}
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if(ok == 0)
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printf("\n\n抱歉, %d 找不到!", input);
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printf("\n");
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return 0;
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}
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